Exhibit 8.1 - Opinion of McGuireWoods LLP - Tax

                        [LETTERHEAD OF MCGUIREWOODS LLP]

                               September 26, 2003

CarMax Auto Funding LLC
4900 Cox Road
Glen Allen, Virginia  23060

                             CarMax Auto Funding LLC
               Registration Statement on Form S-3 (No. 333-107925)
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Ladies and Gentlemen:

                  We have acted as special federal tax counsel for CarMax Auto
Funding LLC, a Delaware limited liability company (the "Company"), in connection
with the above-captioned registration statement (such registration statement,
together with the exhibits and any amendments thereto, the "Registration
Statement"), filed by the Company with the Securities and Exchange Commission
under the Securities Act of 1933, as amended (the "Act"), on August 13, 2003, in
connection with the registration by the Company of Asset Backed Notes (the
"Notes") and Asset Backed Certificates (the "Certificates"). As described in the
Registration Statement, the Notes and the Certificates will be issued from time
to time in series, with each series being issued by a trust (each, a "Trust") to
be formed by the Company pursuant to a Trust Agreement (each, a "Trust
Agreement") between the Company and a trustee designated therein. Each series of
Notes will be issued pursuant to an Indenture (the "Indenture") between the
related Trust and an indenture trustee designated therein. Each series of
Certificates will be issued pursuant to the related Trust Agreement.

                  In connection with our engagement, we have examined and relied
upon the Registration Statement, including the form of prospectus and the two
forms of prospectus supplement included therein (collectively, the
"Prospectus"), the form of Trust Agreement attached as an exhibit thereto, the
form of Indenture attached as an exhibit thereto and such other documents as we
have deemed necessary for purposes of this opinion.

                  The opinion expressed herein is based upon the Internal
Revenue Code of 1986, as amended, administrative rulings, judicial decisions,
proposed, temporary and final Treasury regulations and other applicable
authorities. The statutory provisions, regulations and interpretations upon
which such opinion is based are subject to change, and such changes could apply
retroactively. In addition, there can be no assurance that positions contrary to
those stated in such opinion will not be asserted by the Internal Revenue
Service.

                  Based upon and subject to the forgoing, we are of the opinion
that the statements set forth under the headings "Summary - Tax Status" and
"Material Federal Income Tax Consequences" in the Prospectus, insofar as such
statements constitute matters of law or legal conclusions with respect thereto
and except to the extent qualified therein, accurately describe the material
federal income tax consequences to the holders of the Notes and the
Certificates. We hereby confirm and adopt as our opinions the opinions expressly
set forth under such headings.

                  We note that the Prospectus does not relate to an actual
transaction. As a result, the descriptions of federal income tax consequences
referred to above may be modified in the context of an actual transaction.

                  We hereby consent to the filing of this opinion as an exhibit
to the Registration Statement and to the reference to McGuireWoods LLP under the
heading "Material Federal Income Tax Consequences" in the Prospectus. We do not
admit by giving this consent that we are in the category of persons whose
consent is required under Section 7 of the Act.

                                           Very truly yours,

                                           /s/ MCGUIREWOODS LLP