Large tires:
Press Square, Triangle, Square, Triangle, R1, R1, L2, L2 at the main menu.

Small cars:
Press Square, R2, L2, Triangle, Triangle, L2, R2, Square at the main menu.

"Dude" sounds:
Press R2, R1, L2, R2, Square, Triangle, L1, R1 at the main menu.

TowJam car:
Press Square, Triangle, L1, R1, L2, R2, Square, Triangle at the main menu.

Flat shaded graphics:
Press L1, R1, L2, R2, L1, R1, L2, R2 at the main menu.

Bonus cars:
Enter one of the following passwords to unlock the corresponding bonus car for the indicated player

Car - Player one - Player two
Sol-Aire CX4 - or8b4ork8r 3f89jr33LH - or8b4ork8r 3f89Jr33LH

Slide out - om46domf4f _9lndm_ _cc - owdg8owpdJ 7KHXnw77QM

Formula 5000 - 4wdg84wpds 7k7xnw77QM

Hotwheels 500 yLkMffovnp dQBMToddw8

Super van - op482oph6b 1cpQgp11Jf

Stage Fright - o_jLdo_TJT - cp6o9_ccvr

How to Get The ROCKBUSTER:
In the race road to rustwell, after the jump that gets you wicked air, you go through the first barn thing you see the jump DON'T go off it.
Yougo around the high end of it and hit the lighter colored piece of the house to your right and ram it. Then you see the ROCKBUSTER. Run into it and you have it!