Go to the Start Screen and press the following codes:
Unlimited Ammo: L, R, L, R, L + R, Z.
2X Prize Money: L, R, Z, L, R, Z, L + R.
Extreme Lap Challenge: L, R, L, R , L, R, Z, L + R.
All Teams & Tracks: L, L, R, R, Z, Z, L + R + Z.