<PAGE>
                                                                    EXHIBIT 10.8

                     AMENDMENT TO PROMISSORY NOTES AND LOANS


         This Amendment to Promissory Notes and Loans (this "Amendment"), dated
as of April 15, 2004 (the "Effective Date"), is by and between Boundless Motor
Sports Racing, Inc., a Colorado corporation (the "Maker"), and Paul A. Kruger, a
resident of the State of Florida ("Payee"). Maker and Payee are sometimes each
referred to herein as a "Party" and collectively, as the "Parties".

                                    RECITALS

         A. Maker previously entered into certain Promissory Notes, dated June
3, 2003 and July 1, 2003, under which Maker has borrowed a principal amount of
$50,000 and $600,000 respectively, prior to the Effective Date (the "Notes"),
and subsequently loaned to Maker an additional $1,544,011, on the dates and in
the amounts set forth in Schedule I to this Agreement upon the same terms and
conditions as set forth in the Notes (collectively, the "Advances," and together
with the Notes, the "Loans"). All capitalized terms not otherwise defined herein
have the meanings set forth in the Note.

         B. Maker has requested that Payee loan additional sums to Maker (the
"Additional Advancement") under the Note and Payee has agreed to do so, subject
to the terms and conditions set forth in this Amendment.

         C. NOW, THEREFORE, in consideration of the mutual covenants set forth
herein and for good and valuable consideration, the adequacy, receipt and
sufficiency of which are hereby acknowledged, the Parties hereby agree as
follows:

                                   AGREEMENTS

         1. As of the Effective Date, the interest rate under the Loans is
hereby increased from four percent (4%) to ten percent (10%) per annum, except
as otherwise may be provided in the Notes, which new rate shall be applicable to
all outstanding principal under the Loans.

         2. The Parties shall cause this Amendment to be attached to the Notes.

                                  MISCELLANEOUS

         1. Except as modified and amended hereby, the Loans is and shall remain
in force and effect in accordance with its terms.

         2. This Amendment may be executed in several counterparts, all of which
are identical, each of which shall be deemed an original, and all of which
counterparts together shall constitute one and the same instrument.

         3. This Amendment shall be governed by and construed in accordance
with, the laws of the State of Texas, regardless of the laws that might
otherwise govern under principles of conflicts of laws applicable thereto.



<PAGE>

         EXECUTED as of the date first above written.

                                 BOUNDLESS MOTOR SPORTS RACING, INC.


                                 By:  /s/ THOMAS L. EARNSHAW
                                     -------------------------------
                                     Thomas L. Earnshaw
                                     CFO


                                       2
<PAGE>



                                   SCHEDULE I


<Table>
<Caption>
                 DATE OF LOAN                     AMOUNT OF LOAN
                 ------------                     --------------
<S>                                               <C>
                    10/08/2003                        600,000

                    11/25/2003                         600,000

                    11/25/2003                         115,000

                    01/20/2004                         250,000

                    02/02/2004                        (290,000)

                    01/16/2004                          21,511

                    02/27/2004                          25,000

                    03/16/2004                          87,500

                    03/19/2004                          10,000

                    03/11/2004                          75,000

                    03/31/2004                          50,000


                                             -----------------
                                             $       1,544,011
                                             =================
</Table>