All Reward Cars:
At the Options menu, hold L + R, then press A, B, A, B.
Fast Cars:
At the Options menu, hold L + R, then press X, X, X, X.
Invincible Car:
At the Options menu, hold L + R, then press Y, A, Y, A.
High Acceleration:
At the Options menu, hold L + R, then press Y, Y, Y, Y.
Jump Car with Horn:
At the Options menu, hold L + R, then press X, X, X, Y.
One Hit Kills:
At the Options menu, hold L + R, then press Y, Y, X, X.
All Cameras:
At the Options menu, hold L + R, then press B, B, B, A.
Show Credits:
At the Options menu, hold L + R, then press A, X, X, Y.
Show Speedometer:
At the Options menu, hold L + R, then press Y, Y, B, X.
Turn Secret Car into Red Brick Car:
At the Options menu, hold L + R, then press B, B, Y, X.
Grid Mode:
At the Options menu, hold L + R, then press B, A, B, Y.
Trippy Mode:
At the Options menu, hold L + R, then press Y, B, Y, B.
Glitch:
In level 4 drive any car you want. Go to the bridge and jump off, you HAVE TO ENABLE CAR JUMPING!. Jump off the side of the bridge in your car. Get as far away from the bridge as possible, you will be under water. Drive away from the bridge. If you do not do this the glitch will not work. You will not be on the ground you will be under it! Do not destroy your car or you will not be able to get back up! To get up get in your car and press the d-pad in any direction to reset your car.
(supplied by: tylorscool22)