EXHIBIT 99.8

June 7, 2007

Citibank, N.A.
Confirmations Unit
333 West 34th, 2nd Floor
New York, NY 10001, USA
Tel: (212) 615-8981
Fax: (212) 615-8985

RE: Confirmation of Primary Swap Relating to the Class A-4 Notes

Transaction Reference Number: M072614

Dear Ladies and Gentlemen:

     The purpose of this letter agreement is to confirm the terms and conditions
of the Swap Transaction (the "Primary Swap") entered into between Citibank, N.A.
(the "Counterparty") and Capital Auto Receivables Asset Trust 2007-SN1 (the
"Trust") as of the Trade Date listed below (the "Transaction"). This letter
constitutes a "Confirmation" as referred to in the Primary ISDA Agreement
specified below.

1.   The definitions and provisions contained in the 2000 ISDA Definitions (the
     "Definitions"), as published by the International Swaps and Derivatives
     Association, Inc. ("ISDA"), are incorporated into this Confirmation. In the
     event of any inconsistency between those definitions and provisions and
     this Confirmation, this Confirmation will govern. The parties agree that
     this transaction is a Transaction under the ISDA Master Agreement of the
     parties dated as of June 7, 2007. The agreement is comprised of the printed
     form of such agreement as published by ISDA, as supplemented and modified
     by a Schedule (the "Primary ISDA Agreement").

     This Confirmation constitutes a binding agreement between you and us and
     will supplement, form a part of, and be subject to the Primary ISDA
     Agreement described above as amended and supplemented from time to time.

     The Counterparty and the Trust acknowledge that this Transaction relates to
     the CARAT 2007-SN1 Class A-4 Floating Rate Asset Backed Notes (the "Notes"
     or "Reference Notes") issued by the Trust for value pursuant to and subject
     to the CARAT Indenture.

     Capitalized terms used and not otherwise defined herein, in the Primary
     ISDA Agreement or in the Definitions shall have the meanings assigned to
     them in Exhibit A or Exhibit B hereto, as applicable.

     All references to "dollars" or to "$" shall be references to amounts in
     United States Dollars.

2.   The terms of the particular Transaction to which this Confirmation relates
     are as follows:

     Type of Transaction: Interest Rate Swap.

     Notional Amount: $405,007,000 with respect to the initial Calculation
     Period. The Notional Amount with respect to each Calculation Period
     thereafter shall be equal to the Reference Note Balance as of the close of
     business on the Distribution Date at the beginning of the relevant
     Calculation Period (as set forth in the Calculation Statement (defined
     below) delivered by GMAC to the Counterparty on or prior to the
     Determination Date relating to such Calculation Period pursuant to Section
     3 below).

          Trade Date: May 31, 2007.



     Effective Date: June 7, 2007.

     Termination Date: The earlier of the close of business on (i) February 15,
     2011 and (ii) the Fixed Rate Payer Payment Date on which the Notional
     Amount is reduced to zero; subject to adjustment in accordance with
     Following Business Day Convention.

     Fixed Amounts:

          Fixed Rate Payer: The Trust.

          Fixed Rate Payer Period End Dates: The 15th calendar day of each
          month, commencing June 15, 2007, to and including the Termination
          Date, in each case, subject to adjustment in accordance with the
          Following Business Day Convention.

          Fixed Rate Payer Payment Date: With respect to each Calculation
          Period, the day that is one Business Day prior to the first
          Distribution Date to occur following the last day of such Calculation
          Period.

          Fixed Rate: 5.370%.

          Fixed Rate Day Count Fraction: 30/360.

     Floating Amounts:

          Floating Rate Payer: The Counterparty.

          Floating Rate Payer Period End Dates: Each Fixed Rate Payer Period End
          Date.

          Floating Rate Payer Payment Dates: Each Fixed Rate Payer Payment Date.

          Reset Dates: With respect to each Calculation Period, the first day of
          such Calculation Period.

          Floating Rate Option: LIBOR (as defined in Exhibit A hereto).

          Spread: Plus 10 basis points.

          Floating Rate Day Count Fraction: Actual/360.

          Compounding: Inapplicable.

     Business Days for Payment: New York (New York), Detroit (Michigan) and
     Chicago (Illinois).

     Calculation Agent: GMAC LLC, as agent for and on behalf of the Trust.

     Default Rate: For any United States Dollar payments, the rate determined
     under the option entitled "USD Federal Funds - H.15" plus 1% using daily
     Reset Dates. The Default Rate will be applied on the basis of Compounding
     as if the overdue amount were a Notional Amount and using daily Compounding
     Dates, and interest will accrue and be payable before as well as after
     judgment.

3.   Calculations and Notifications: On or before each Determination Date, the
     Calculation Agent shall determine the Fixed Amount due to the Counterparty
     on the next succeeding Fixed Rate Payer Payment Date and the Floating
     Amount due to the Trust on the next succeeding Floating Rate Payer


                                       2



     Payment Date and the Calculation Agent shall notify the Counterparty in
     writing of both (i) the Floating Rate and (ii) the amount of such payment.

     In addition, on each Determination Date the Trust shall deliver to the
     Counterparty (by facsimile with hard copy to follow) a statement (the
     "Calculation Statement") setting forth with respect to the close of
     business on the immediately preceding Distribution Date the Reference Note
     Balance as of such Distribution Date.

     The Trust will give the Counterparty prompt written notice of any Default
     under the CARAT Indenture.

4.   Credit Downgrade:

     (A) S&P Downgrade: In the event that the Joint Probability is reduced below
     AA- in the case of S&P, the Counterparty shall promptly notify the Trust
     (and any permitted assignee or transferee of the Trust) and GMAC of such
     event and (unless, within thirty (30) days after such reduction, the
     applicable Rating Agency has reconfirmed the ratings of the Reference Notes
     and the Other Securities that were in effect immediately prior to such
     reduction) the Counterparty shall within thirty (30) days of receipt of
     notice of such reduction, with the prior written confirmation of the
     applicable Rating Agency that such arrangement will not result in the
     reduction of the rating of any of the Reference Notes or the Other
     Securities existing immediately prior to the reduction of the applicable
     Joint Probability, either:

          (1) (x) obtain a substitute swap provider (the "Substitute Swap
          Provider") acceptable to the Trust, such acceptance to be deemed to
          exist unless the Indenture Trustee provides a basis for objection to
          such Substitute Swap Provider within two (2) Business Days of receipt
          of notice from the Counterparty, and replace this Transaction with a
          swap transaction on substantially similar terms or with such other
          amendments as consented to in writing by the Trust (which consent
          shall not be unreasonably withheld), provided such replacement would
          result in an S&P Joint Probability of at least AA-, except that such
          Substitute Swap Provider shall thenceforth be the "Counterparty"
          hereunder; or (y) replace, with the consent of the then-current
          Offsetting Counterparty, the swap transaction with the then-current
          Offsetting Counterparty with a swap transaction with a replacement
          Offsetting Counterparty or enter into a swap transaction with another
          party such that such party shall be acting as an intermediary between
          the Counterparty and the then-current Offsetting Counterparty (such
          replacement or intermediary being the "Replacement Offsetting
          Counterparty"), in either case on terms approved by the Rating
          Agencies; or

          (2) enter into an ISDA Credit Support Annex ("CSA") with the Trust
          mutually acceptable to the Trust and the Counterparty and, if the
          Counterparty is required to post collateral pursuant to such CSA, at
          the time such CSA is entered into, the Counterparty shall request its
          legal counsel to deliver to each applicable Rating Agency an opinion
          as to the enforceability thereof; or

          (3) enter into such other credit support arrangements acceptable to
          the applicable Rating Agency to assure performance by the Counterparty
          of its obligations under this Transaction.


                                        3



     Notwithstanding the foregoing, in the event that the Joint Probability is
     reduced below A- in the case of S&P, then the Counterparty shall promptly
     notify the Trust (and any permitted assignee or transferee of the Trust)
     and the Offsetting Counterparty of such event and (unless, within thirty
     (30) days after such reduction the applicable Rating Agency has reconfirmed
     the ratings of the Reference Notes and the Other Securities that were in
     effect immediately prior to such reduction) the Counterparty shall within
     thirty (30) days of receipt of notice of such reduction, with the prior
     written confirmation of the applicable Rating Agency that such arrangement
     will not result in the reduction of the rating of any of the Reference
     Notes or the Other Securities existing immediately prior to the reduction
     of the S&P Joint Probability as a direct result of the reduction of such
     Joint Probability, obtain a Substitute Swap Provider acceptable to the
     Trust, such acceptance to be deemed to exist unless the Indenture Trustee
     provides a basis for objection to such Substitute Swap Provider within two
     (2) Business Days of receipt of notice from the Counterparty, and replace
     this Transaction with a swap transaction on substantially similar terms or
     with such other amendments as consented to in writing by the Trust (which
     consent shall not be unreasonably withheld) provided such replacement would
     result in an S&P Joint Probability of at least AA-, except that such
     Substitute Swap Provider shall thenceforth be the "Counterparty" hereunder.

     (B) Fitch Downgrade: In the event that the short-term rating assigned by
     Fitch to the unsecured, unsubordinated debt of the Counterparty falls below
     "F1" or the long-term debt rating assigned by Fitch to the unsecured,
     unsubordinated debt of the Counterparty falls below "A" (such downgrade, a
     "FITCH DOWNGRADE"), then, the Counterparty shall promptly notify the Trust
     (and any permitted assignee or transferee of the Trust) and GMAC of such
     Fitch Downgrade and the Counterparty shall within thirty (30) days of
     receipt of notice of such reduction, either:

          (1) (x) obtain a Substitute Swap Provider acceptable to the Trust,
          such acceptance to be deemed to exist unless the Indenture Trustee
          provides a basis for objection to such Substitute Swap Provider within
          two (2) Business Days of receipt of notice from the Counterparty, and
          replace this Transaction with a swap transaction on substantially
          similar terms or with such other amendments as consented to in writing
          by the Trust (which consent shall not be unreasonably withheld),
          provided such replacement would result in an Fitch unsecured,
          unsubordinated debt rating of at least "A" (long-term) and "F1"
          (short-term), except that such Substitute Swap Provider shall
          thenceforth be the "Counterparty" hereunder; or

          (2) enter into a CSA with the Trust mutually acceptable to the Trust
          and the Counterparty and on terms approved by Fitch at the time such
          CSA is entered into; or

          (3) arrange for an entity with a rating assigned by Fitch to the
          unsecured, unsubordinated debt of at least "F1" (short-term) and "A"
          (long-term) to provide an unconditional guaranty for its obligations
          hereunder; or

          (4) enter into such other credit support arrangements acceptable to
          Fitch to assure performance by the Counterparty of its obligations
          under this Transaction.

     Notwithstanding the forgoing, in the event that the short-term rating
     assigned by Fitch to the unsecured, unsubordinated debt of the Counterparty
     falls below "F3" or the long-term debt rating assigned by Fitch to the
     unsecured, unsubordinated debt of the Counterparty falls below "BBB-", then
     the Counterparty shall promptly notify the Trust (and any permitted
     assignee or transferee of the Trust) and GMAC of such Fitch Additional
     Downgrade and the Counterparty shall within thirty (30)


                                        4



     days of receipt of notice of such reduction, satisfy the requirements set
     forth in either sub-paragraph 4(B)(1), (3) or (4) above.

     Upon any replacement of this Transaction with a swap transaction with a
     Substitute Swap Provider, this Transaction shall terminate without any
     payment by either party hereto and any and all collateral posted by the
     Counterparty shall be returned to it within three (3) Business Days and any
     other form of collateral arrangement (including letters of credit, surety
     bond or other guarantee) provided by or on behalf of the Counterparty shall
     terminate.

     In the event that the Counterparty fails to satisfy its obligations set
     forth above in this Section 4, the Trust or any permitted assignee or
     transferee of the Trust shall have the option, exercisable in its
     discretion and with regard to the interests of the CARAT 2007-SN1
     Noteholders, within ten (10) Business Days following the date of expiry of
     the thirty (30) day period after the date of receipt of notice of the
     reduction (unless, within thirty (30) days of receipt of notice of such
     reduction, the applicable Rating Agency has reconfirmed the rating of the
     Reference Notes that was in effect immediately prior to such reduction), to
     designate (in writing) an Early Termination Date on the basis that such
     failure shall be treated as a Termination Event with the Counterparty as
     the Affected Party. For the avoidance of doubt, the Counterparty and the
     Trust acknowledge and agree that any such failure shall not constitute an
     Event of Default.

5.   Account Details:

          Payments to Fixed Rate Payer:

               The Bank of New York - New York, NY
               ABA #021000018
               For credit to GLA: 211705
               For Final Credit to: 775815
               Account of: CARAT 2007-SN1
               Attn: Keith Richardson (312) 827-8572

          Payments to Floating Rate Payer:

               Citibank, N.A.
               ABA: 021000089
               Swift: CITIUS33
               Account Number: 00167679

6.   Limited Recourse: Notwithstanding anything to the contrary contained herein
     but without limiting the Counterparty's rights under Section 5(a)(i) of the
     Primary ISDA Agreement, all of the obligations of the Trust shall be
     payable by the Trust only at the times and to the extent of funds available
     therefor under the Trust Sale and Administration Agreement and, to the
     extent such funds are not available or are insufficient for the payment
     thereof, shall not constitute a claim against the Trust to the extent of
     such unavailability or insufficiency until such time as, and then to the
     extent that, the Trust has assets sufficient to pay such prior deficiency.
     This paragraph shall survive the termination of this Agreement but in all
     cases shall expire one year and one day after the final payment with
     respect to all notes and certificates issued by the Trust.

7.   Limitation of Liability: It is expressly understood and agreed by the
     parties hereto that (a) this Agreement is executed and delivered by
     Deutsche Bank Trust Company Delaware, not individually or personally but
     solely as CARAT Owner Trustee of the Trust in the exercise of the powers
     and authority conferred and vested in it, (b) each of the representations,
     undertakings and agreements herein made on the part of the Trust is made
     and intended not as personal representations,


                                       5



     undertakings and agreements by Deutsche Bank Trust Company Delaware but is
     made and intended for the purpose of binding only the Trust, (c) nothing
     herein contained shall be construed as creating any liability on Deutsche
     Bank Trust Company Delaware, individually or personally, to perform any
     covenant either expressed or implied contained herein, all such liability,
     if any, being expressly waived by the parties hereto and by any Person
     claiming by, through or under the parties hereto and (d) under no
     circumstances shall Deutsche Bank Trust Company Delaware be personally
     liable for the payment of any indebtedness or expenses of the Trust or be
     liable for the breach or failure of any obligation, representation,
     warranty or covenant made or undertaken by the Trust under this Agreement
     or any other related documents.

8.   To the extent that a capitalized term in this Transaction is defined by
     reference to a related definition contained in any CARAT Basic Document,
     for purposes of this Transaction only, such capitalized term shall be
     deemed to be amended only if the amendment of the term in a CARAT Basic
     Document relating to such capitalized term occurs with the prior written
     consent of the Counterparty.

                                     * * * *


                                       6



     Please confirm that the foregoing correctly sets forth the terms of our
agreement by executing the copy of this Confirmation enclosed for that purpose
and returning it to us.

                                        CAPITAL AUTO RECEIVABLES ASSET
                                        TRUST 2007-SN1

                                        By: DEUTSCHE BANK TRUST COMPANY
                                            DELAWARE, not in its individual
                                            capacity but solely as CARAT Owner
                                            Trustee


                                        By: /s/ Jenna Kaufman
                                            ------------------------------------
                                        Name: Jenna Kaufman
                                        Title: Attorney-In-Fact


                                        By: /s/ Aranka  R. Paul
                                            ------------------------------------
                                        Name: Aranka R. Paul
                                        Title: Attorney-In-Fact


Accepted and confirmed as of the date
first written above:

CITIBANK, N.A.


By: /s/ Frank A. Licciardello
    --------------------------------
Name: Frank A. Licciardello
Title: Authorized Signatory


Acknowledged and agreed as of the
date first written above:

GMAC LLC,
solely as Calculation Agent


By: /s/ P.M. Surhigh
    ---------------------------------
Name: P.M. Surhigh
Title: Director - U.S. &
       International Funding Group

   [SIGNATURE PAGE CARAT 2007-SN1 - PRIMARY INTEREST RATE SWAP (CONFIRMATION)]



                                    EXHIBIT A

The following terms shall have the following meanings in this Confirmation:

     "Calculation Period": means, with respect to each party hereunder, each
period from, and including one Period End Date of that party to, but excluding,
the next following Period End Date of that party during the Term of the Swap
Transaction, except that the initial Calculation Period for that party will
commence on, and include, the Effective Date.

     "CARAT Indenture": the CARAT Indenture, dated as of the date hereof between
the Trust and the CARAT Indenture Trustee, as amended and supplemented from time
to time in accordance with its terms.

     "CARAT Indenture Trustee": Citibank, N.A., not in its individual capacity
but solely as trustee under the CARAT Indenture, or any successor trustee under
the CARAT Indenture.

     "Determination Date": the tenth (10th) day of each calendar month, or if
such tenth (10th) day is not a Business Day, the next succeeding Business Day.

     "Distribution Date": the fifteenth (15th) day of each succeeding calendar
month following the Effective Date or, if such fifteenth (15th) day is not a
Business Day, the next such succeeding Business Day, commencing June 15, 2007.

     "LIBOR": means for any Calculation Period with respect to each Floating
Rate Payer Payment Date, the rate for deposits in U.S. Dollars for a period of
one month which appears on the Reuters Telerate Service Page 3750 as of 11:00
a.m., London time, on the day that is two LIBOR Business Days prior to the first
day of the Calculation Period preceding such Floating Rate Payer Payment Date
(or, in the case of the initial Floating Rate Payer Payment Date, two LIBOR
Business Days prior to the Closing Date). If the rate does not appear on that
date on Telerate Service Page 3750 (or any other page as may replace that page
on that service, or if that service is no longer offered, any other service
commonly used in the interbank market for displaying LIBOR or comparable rates
as may be selected by the CARAT Indenture Trustee after consultation with the
Seller), then LIBOR will be the Reference Bank Rate.

     "LIBOR Business Day": any day other than a Saturday, Sunday or any other
day on which banks in London are required or authorized to be closed.

     "Other Securities": Class A-1 Notes, Class A-2 Notes, Class A-3 Notes,
Class B Notes, Class C Notes, and Class D Notes.

     "Reference Bank Rate": means for any Calculation Period for any Floating
Rate Payer Payment Date, the per annum rate determined on the basis of the rates
at which deposits in U.S. Dollars are offered by the reference banks (which will
be four major banks that are engaged in transactions in the London interbank
market, selected by the Calculation Agent) as of 11:00 a.m., London time, on the
day that is two LIBOR Business Days prior to the first day of the Calculation
Period preceding such Floating Rate Payer Payment Date to prime banks in the
London interbank market for a period of one month, in amounts approximately
equal to the principal amount of the Reference Notes then outstanding. The
Calculation Agent will request the principal London office of each of the
reference banks to provide a quotation of its rate. If at least two quotations
are provided, the rate will be the arithmetic mean of the quotations, rounded
upwards to the nearest one-sixteenth of one percent. If on that date fewer than
two quotations are provided as requested, the rate will be the arithmetic mean,
rounded upwards to the nearest one-sixteenth of one percent, of the rates quoted
by one or more major banks in New York City, selected by the Calculation Agent,
as of 11:00 a.m., New York City time, on that date to leading European banks for
United States dollar deposits for a period of one month in


                                      A-1



amounts approximately equal to the principal amount of the Reference Notes then
outstanding. If no quotation can be obtained, then LIBOR will be the rate for
the prior Floating Rate Payer Payment Date.

     "Reference Note Balance": as of the Effective Date, $405,007,000 and, with
respect to each Distribution Date thereafter, the aggregate principal balance of
any and all outstanding Reference Notes.

     "Seller": Capital Auto Receivables, Inc., which has executed the Trust Sale
and Administration Agreement as the Seller, or its successor in interest
pursuant to Section 3.03 of the Trust Sale and Administration Agreement.

     "Trust Sale and Administration Agreement": the Trust Sale and
Administration Agreement, dated as of the date hereof between the Seller, GMAC
LLC, as Trust Administrator, and the Trust, as amended, modified and
supplemented from time to time in accordance with its term.


                                      A-2



                                    EXHIBIT B

     "Contingent Party": the Offsetting Counterparty or the Replacement
Offsetting Counterparty, as applicable.

     "DBRS": Dominion Bond Rating Service, Inc. or any successor thereto.

     "Fallback Swap Transaction": the swap transaction entered into by the Trust
and Offsetting Counterparty relating to the Class A-4 Floating Rate Asset Backed
Notes.

     "Fitch": Fitch, Inc., or any successor thereto.

     "Joint Probability": the S&P Joint Probability.

     "Offsetting Counterparty" means GMAC LLC or any successor thereto ("GMAC")
under the Fallback Swap Transaction entered into between the Trust and GMAC.

     "Primary Party": the Counterparty, unless a Substitute Swap Provider has
been obtained, in which case it shall be the Substitute Swap Provider or, if
applicable, a guarantor thereof.

     "Rating Agency": each of DBRS, S&P and Fitch.

     "S&P": Standard & Poor's Ratings Services and its successors.

     "S&P Joint Probability" means the joint probability determined by S&P of
the long-term likelihood of payment under the interest rate swap determined by
locating the intersection of the Counterparty's long term senior unsecured debt
rating and the Contingent Party's long-term senior unsecured debt rating in the
following table:

                          IMPLIED JOINT SUPPORT RATING

PRIMARY PARTY



CONTINGENT
PARTY        AAA   AA+    AA   AA-    A+    A     A-   BBB+    BBB   BBB-
- ----------   ---   ---   ---   ---   ---   ---   ---   ----   ----   ----
                                       
AAA          AAA   AAA   AAA   AAA   AAA   AAA   AAA   AAA    AAA    AAA
AA+          AAA   AAA   AAA   AAA   AAA   AAA   AAA   AAA    AAA    AAA
AA           AAA   AAA   AAA   AAA   AAA   AAA   AAA   AA+    AA+    AA+
AA-          AAA   AAA   AAA   AA+   AA+   AA+   AA+   AA+    AA+    AA
A+           AAA   AAA   AAA   AA+   AA+   AA+   AA+   AA     AA     AA-
A            AAA   AAA   AAA   AA+   AA+   AA    AA    AA-    AA-    A+
A-           AAA   AAA   AAA   AA+   AA+   AA    AA-   A+     A+     A
BBB+         AAA   AAA   AA+   AA+   AA    AA-   A+    A      A      A-
BBB          AAA   AAA   AA+   AA+   AA    AA-   A+    A      A-     BBB+
BBB-         AAA   AAA   AA+   AA    AA-   A+    A     A-     BBB+   BBB


Notwithstanding the foregoing, (i) in the event that the long-term senior
unsecured debt rating of either the Primary Party or the Contingent Party is
rated below BBB- by S&P, then the S&P Joint Probability shall be the higher of
the then current long-term senior unsecured debt rating of the Primary Party and
the Contingent Party and (ii) in the event that under the Triparty Agreement the
Offsetting Counterparty has acceded to the rights of the Counterparty and no
swap transaction has been effected with an additional contingent counterparty or
replacement swap counterparty under the circumstances contemplated by Section
2.02 of the Triparty


                                      B-1



Agreement, then the term "S&P Joint Probability" shall refer to the Offsetting
Counterparty's long-term senior unsecured credit rating assigned by S&P (and,
for the avoidance of doubt, the obligations of the Counterparty specified in
Section 4 of this Confirmation shall constitute obligations of the Offsetting
Counterparty).

     "Triparty Agreement": the Triparty Contingent Assignment Agreement dated as
of the Effective Date among the Trust, the Offsetting Counterparty and the
Counterparty.


                                      B-2