At the "Press Start" screen, press L + R, C-Left, C-Right, L + R. Press Start, then at the mode selection screen, hold Z and tap L until "Cheat mode" appears at the bottom of the screen. Cheat mode includes special modes and the option to unlock bonus cars.
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Game Shark Codes
Unlock All Tracks
80140D1A 0070
Unlock All Cars
80140D1F 003F
Unlock Champ
80140D28 0001
Enable Expert Times
80140D1C 0031
