Use the following trick to change your bonus code. For example, if you want to use the cheats for 5205 but your number is different. Delete your game file from your memory card, then reload the game. You will have a new bonus code. Repeat this process until you get the desired number.
Honda Tournament
Enter everything as a case-sensitive code (demo version).
Enter Q5QC6HTKTWP1B as a code (bonus code 1027).
Enter X4K7T2DPL7VU5 as a code (bonus code 5205).
Enter Q2MH3669N7859 as a code (bonus code 7510).
Alternately, successfully complete World Tour mode.
Invincible cars
Enter 6H61G288KBVP5 as a code (bonus code 2945).
Michael Andretti's 2003 IRL car
Enter Michael Andretti as a case-sensitive code to unlock Michael Andretti's 2003 IRL car.
Note
Some of the game's cheats are matched to the bonus code of each game, which will vary. Some of the following codes will only work with discs that have the same bonus code.
Richard Petty's stock car
Enter Richard Petty as a case-sensitive code to unlock Richard Petty's stock car.