Invisibility 
Pause the game and press R1, L1(2), R2, L1(2), L2. If you entered the code correctly, you will hear a sound.

Lighter cars 
Pause the game and press L1, R1(2), L2, R2(2). If you entered the code correctly, you will hear a sound.

No gravity 
Pause the game and press R1, R2, R1, R2, Up(3). If you entered the code correctly, you will hear a sound.

Increase time warp 
Pause the game and press R1, L1, L2, R2, Right(3). If you entered the code correctly, you will hear a sound.

Decrease time warp 
Pause the game and press R2, L2, L1, R1, Left(3). If you entered the code correctly, you will hear a sound.