All Cars and Tracks
When you start the game go down to "sign in" then move over to "password". Then for all cars and tracks put in 1 of these 3 passwords:
_WYVW2LVDW VTXWWVWWWF
OR,
_WYVVZCVDV VTXVVVVVVN
OR
_WYZKZ1VDD OTX1TRGHSV
submitted by Danny J. and JD Person9

Drive Tow Jam Car
Highlight Options at the main menu and press up-C, down-C, Z, R, left-C, right-C, up-C, down-C.
submitted by Marc Forest-Smith, Luke Katus and Mike

Mirror Mode
Highlight Options at the main menu, then press Z, R, Z, Z, R, Z, Z, Z.

Race at Night
Highlight Options at the main menu, then press up-C, up-C], down-C, down-C, left-C, right-C, left-C, right-C.

Secret Places in Snake River Mine
1. At the beginning of Snake River Mine (after the first loop-the-loop) you will take a jump. You will notice a pathway on the right side. Get on to the pathway and you will have your first secret place.

2. Near the middle of the lap you will notice a side place with about two trees and some boulders. Smash into the boulders to break them and you will have your second secret place.

3. After the green and red loop-the-loop you will take a small jump. Get onto the raised place on your right side and smash anything that gets in your way and you will have the third secret place.
submitted by Matt

Stealth Mode
Highlight Options at the main menu, then press left-C, Z, Z, up-C, left-C, R, down-C, up-C.

Unlimited Turbo
Highlight Options at the main menu, then press right-C, Z, up-C, down-C,R, left-C, Z, right-C.

Wireframe Mode
Highlight Options at the main menu, then press up-C, Z, down-C, left-C, up-C, Z, down-C, left-C.