Cheats
Enter these codes at the Main Title Screen.

Circuit Tracks	DOWN, R, R, R, BLACK, BLACK, BLACK, X
Drag Tracks	RIGHT, X, LEFT, R, X, L, WHITE, BLACK
Drift Physics	R, UP, UP, UP, DOWN, DOWN, DOWN, L
Drift Tracks	LEFT, LEFT, LEFT, LEFT, RIGHT, BLACK, R, WHITE
Level 2 Visual Parts	DOWN, LEFT, UP, DOWN, R, BLACK, BLACK, X
Mystical Car	UP, RIGHT, UP, UP, DOWN, RIGHT, UP, RIGHT
Sprint Tracks	UP, BLACK, BLACK, BLACK, R, DOWN, DOWN, DOWN

Unlockables
To unlock the following complete Underground Mode:

All Visual Upgrades (single and multiplayer mode)
All Accessories
All Body Parts
All Decals
All Paint Colors
All Rims