Document:

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                                                                 EXHIBIT 10.31.4

                                 PROMISSORY NOTE

US$4,174,078
                                                          Fairfield, Connecticut
Due Date: March 1, 2021                                    Dated:  March 1, 2001

         FOR VALUE RECEIVED the undersigned (the "Borrower"), promise to pay to
the order of UAG CONNECTICUT, LLC, a Delaware limited liability company (the
"Lender"), at its office set forth below or at such other place as Lender may
designate in writing, the principal sum of Four Million One Hundred and Seventy
Four Thousand and Seventy Eight Dollars ($4,174,078) in consecutive equal
quarterly payments of Fifty Two Thousand One Hundred Seventy Five and 98/100
Dollars ($52,175.98) with interest as hereinafter provided, all in lawful money
of the United States of America.

         Interest shall accrue on the outstanding principal balance hereof at a
per annum rate, calculated on a 360 day basis, equal to the average of (i) the
one-month London Interbank Offered Rate ("LIBO Rate") published in the Wall
Street Journal the first business day of each month during the term of this Note
and (ii) the LIBO Rate for the 16th day of the immediately preceding month (or,
if such date is not a business day, for the immediately preceding business day)
plus Two Hundred Twenty Five basis points (2.25%). All outstanding principal and
all accrued and unpaid interest shall be due on March 1, 2021.

         This Note may be prepaid, in full or in part without penalty. All
partial prepayments shall be applied against the last accruing installment or
amount due under this Note and no partial prepayments shall affect the
obligation of Borrower to continue making all payments specified in this Note
until the entire unpaid principal and all accrued interest shall have been paid
in full.

         Borrower expressly assumes all risks of loss or delay in the delivery
of any payment made by mail, and no course of conduct or dealing shall affect
Borrower's assumption of these risks.

         If an Event of Default, as defined below, occurs, then, Lender shall
have the right, as its sole option, to declare the entire balance of principal
then remaining unpaid, with accrued interest thereon (the "Debt"), immediately
due and payable without presentment, demand, or notice of any kinds, all of
which are expressly waived by Borrowers. Thereafter, the Debt shall bear
interest at the maximum interest rate permitted by law, until paid in full. The
occurrence of the following constitutes an "Event of Default:" the Borrower
fails to make full and timely payments of principal and interest when due under
this Note.

         Acceptance by Lender of any payment in an amount less than the amount
then due shall be deemed an acceptance on account only, and Borrower's failure
to pay the entire amount due shall be and continue to be an event of default.
Borrower do hereby jointly and severally waive presentment for payment, demand,
notice of nonpayment, notice of protest or

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protest of this Note and any Lender diligence in collection or bringing suit,
and do hereby consent to any and all extensions of time, renewals, waivers, or
modifications as may be granted by Lender with respect to payment or any other
provisions of this Note and to the release of any collateral or any part
thereof, with or without substitution. The liability of Borrower under this Note
shall be absolute and unconditional, without regard to the liability of any
other person. Borrower agrees to pay all of Lender's costs incurred in the
collection of this Note, including reasonable attorney fees. This Note shall be
deemed to have been executed in, and all rights and obligations hereunder shall
be governed by, the laws of the State of Connecticut.

         The obligations of Borrower to Lender hereunder are secured in
accordance with the terms of a Pledge Agreement dated March 1, 2001 by and
between Borrower, Lender and Automotive Group Realty, LLC. Notwithstanding
anything herein to the contrary, Borrower's payments of the Debt are subject to
Section 8.5 of the Operating Agreement dated March 1, 2001 by and between
Borrower and Lender.

         All amounts set forth in this Note are in United States of America
dollars and currency ("US"), unless otherwise noted.

BORROWER ADDRESS:                               BORROWER:

342 West Putnam Avenue                          THE MILLER CONTINENTAL
Greenwich, CT  06838                            GROUP LLC
Attn: Richard S. Koppelman

                                                /s/ Richard S. Koppelman
                                                ------------------------
                                                By:    Richard S. Koppelman
                                                Its:   Manager

LENDER ADDRESS:

UAG Connecticut, LLC
One Harmon Plaza
9TH Floor
Secaucus, NJ  07094
Attn: Robert T. O'Shaughnessy

                                      -2-<PAGE>   1
                                                                 EXHIBIT 10.31.5

                                                March 1, 2001

UAG Connecticut I, LLC
13400 Outer Drive West, B-36
Detroit, MI 48239

UAG Realty, LLC                                 Automotive Group Realty, LLC
13400 Outer Drive West, B-36                    13400 Outer Drive West
Detroit, MI 48239                               Detroit, MI 48239

UAG Connecticut, LLC                            The Miller Continental Group LLC
13400 Outer Drive West, B-36                    342 West Putnam Avenue
Detroit, MI 48239                               Greenwich, CT  06838

         RE: Operating Agreement (the "Agreement") dated March 1, 2001, by and
         between The Miller Continental Group LLC ("Miller") and UAG
         Connecticut, LLC ("UAG") relating to the ownership of limited liability
         company membership interests of UAG Connecticut I, LLC (the "Company").

Gentlemen:

         In connection with the captioned Agreement, and to induce Miller to
enter into and complete the transactions contemplated by the captioned
Agreement, Automotive Group Realty, LLC, a wholly owned subsidiary of Penske
Corporation ("AGR"), UAG, UAG Realty, LLC ("UAG Realty") and the Company have
all agreed to execute and deliver to Miller this letter setting forth certain
understandings with respect to the real property underlying the business
operations of the Company and its subsidiaries.

         On December 19, 2000, AGR purchased from UAG Realty the real property
(referred to herein, together with any property subsequently acquired by AGR in
connection with the Company's operations, as the "Property") described on the
attached Schedule A for the purchase prices listed for each parcel on the
attached Schedule A (such purchase prices being referred to both individually
with respect to each parcel of Property and collectively with respect to all or
a portion of the parcels of Property as the "2000 Property FMV"). The Property
is leased by UAG Realty from AGR pursuant to a Lease Agreement dated September
29, 2000 as amended, and as may be amended from time to time, (the "Lease"), and
the Company subleases the Property from UAG Realty.

         In connection with the execution and delivery of this letter, Miller,
UAG and the Company each entered into the Agreement which, among other things,
conveys a 20% ownership interest in the Company to Miller. The parties hereto

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intend to convey to Miller a 20% share of appreciation in the Property for
Miller's guarantee of up to twenty percent (20%) of the rent payments due under
the Lease, on the terms and conditions set forth below.

         So long as Miller is not in default of its obligations under the
Agreement and UAG Realty is not in default of its obligations under the Lease,
upon the sale and transfer of all or any of the Properties by AGR, AGR shall pay
to Miller promptly upon completion of any such sale or transfer an amount equal
to twenty percent (20%) of the positive difference between (i) the actual
proceeds received by AGR on the date of the sale or transfer of the Property as
sales price, net of all sales related costs including, but not limited to,
transfer taxes, broker commissions and title policies, of the Property or
Properties sold or otherwise transferred by AGR (the "Net Sale Proceeds") and
(ii) the 2000 Property FMV with respect to each parcel or parcels of Property
sold or otherwise transferred by AGR. If the amount calculated pursuant to the
immediately preceding sentence is less than zero, then Miller agrees to pay to
AGR promptly upon completion of any such sale or transfer or an amount equal to
twenty percent (20%) of the difference between (i) the 2000 Property FMV with
respect to each parcel or parcels of Property sold or otherwise transferred by
AGR, and (ii) the Net Sales Proceeds; provided, however, that the foregoing
obligations of Miller may only be satisfied from proceeds from the Collateral
(as defined below), if any, and except for the Collateral or proceeds therefrom
AGR shall have no recourse against Miller or any other person for the foregoing
obligations of Miller.

         In consideration for the interest conveyed herein, Miller agrees to
guarantee to AGR the payment of up to twenty percent (20%) of the monthly
payment obligation of Base Annual Rent (as defined in the Lease) made by UAG
Realty in accordance with the terms of the Lease as such Base Annual Rent may be
increased or decreased from time to time. This guarantee shall terminate with
respect to each Property upon the sale and transfer of that Property by AGR.
This guaranty is secured by Miller's limited liability ownership interest in the
Company (the "Collateral") which is pledged to AGR and UAG in accordance with a
Pledge Agreement of even date herewith. UAG Realty will use its best commercial
efforts to make timely lease payments. AGR shall copy Miller on any written
notice of an Event of Default (as defined in the Lease) provided to UAG Realty
under the Lease with respect to all or any of the Properties and agrees to
provide Miller with an opportunity to cure such default on the same terms that
the Lease permits UAG Realty the opportunity to cure an Event of Default.

         The parties acknowledge that the amount of the payments made under the
Lease to AGR has been structured to provide AGR with sufficient funds to pay the
interest only on its mortgage loan relating to the Property together with a
reasonable sum above such interest costs to reimburse AGR for expenses incurred
in connection with its administration of the Property. While this Agreement is
in effect, Miller shall have the right to participate in any net refinancing
proceeds relating to the Property on the twenty percent (20%) basis set forth
above, provided that Miller agrees to apply its guarantee to any additional
amount of Lease payments made as a result of the refinancing.

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         The obligations of AGR and Miller hereunder shall terminate upon the
expiration of the term of the Lease, as extended from time to time.

         This agreement shall not serve to eliminate, modify or alter the
obligations of UAG Realty under the Lease and UAG Realty hereby reaffirms its
obligations thereunder.

UAG CONNECTICUT I, LLC                  AUTOMOTIVE GROUP REALTY, LLC

/s/ Robert H. Kurnick, Jr.              /s/ Peter E. Mogk
--------------------------              -----------------
By:      Robert H. Kurnick, Jr.         By:      Peter E. Mogk
Its:     Secretary                      Its:     Treasurer

UAG REALTY, LLC                         THE MILLER CONTINENTAL
                                        GROUP LLC

/s/ Robert H. Kurnick, Jr.              /s/ Richard S. Koppelman
--------------------------              ------------------------
By:      Robert H. Kurnick, Jr.         By:      Richard S. Koppelman
Its:     Secretary                      Its:     Manager

UAG CONNECTICUT, LLC

/s/ Robert H. Kurnick, Jr.
--------------------------
By:      Robert H. Kurnick, Jr.
Its:     Assistant Secretary

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                                  SCHEDULE "A"

<TABLE>
<CAPTION>
                       Property                                         Agreed Upon Current
                       --------                                         -------------------
                                                                         Fair Market Value
                                                                         -----------------
<S>                                                                     <C>
         165 Commerce Drive                                                  $3,500,000
         415-445 Commerce Drive                                              $4,000,000
         475 Commerce Drive                                                  $2,500,000
         102 Linwood                                                         $3,500,000
         80 Commerce Drive                                                   $  305,000
                                                                             ----------
                                                                            $13,805,000
</TABLE>

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