TechLookz

No Gravity:
Pause the game and press R1, R2, R1, R2, Up, Up, Up.

Increase Time Warp:
Pause the game and press R1, L1, L2, R2, Right, Right, Right.

Decrease Time Warp:
Pause the game and press R2, L2, L1, R1, Left, Left, Left.
To undo the code, simply re-enter it.

Make Cars Lighter:
To make your ride a little lighter, pause the game and press these buttons: L1, R1, R1, L2, R2, R2. A sound will confirm correct entry. To undo the code, simply reenter it.

Invisibility:
To become invisible, pause the game, then press R1, L1, L1, R2, L1, L1, L2. A sound will confirm correct entry. To undo the code, simply reenter it.

What You Unlock By Beating Missions:
Beat the missions listed to get the corresponding prize:
Super Buggy: Available at beginning of the game
Super Buggy Boost: Mission 3
D-5 Hondo: Training Mission 3
D-5 Hondo Oil Slick: Mission 8
Baja Truck: Mission 4
Baja Truck Bombs: Mission 7
ATV Monster: Mission 10
ATV Monsters Speed Burst: Mission 14
Du Monde: Mission 13
Du Monde Oil Slick: Mission 21
Sahara Special: Mission 17
Sahara Smoke Screen: Mission 18
Grenadier: Mission 24
Grenadier Bombs: Mission 25
Kavostov Halftrack: Mission 27
Kavostov Halftracks Smoke Screen: Mission 29
Vietnam Map: Mission 9
Georgian Russia Winter Map: Mission 22