Any time during the game (main menu, pause screen, stage select, and etc.) enter L1, L1, L2, L2, R2, R2, R1, R1 and then all of the top buttons at the same time. A message should appear.
Never lose XG career races:
Follow the set up above except enter: L1 + R1 + L2 + R2, then hit L2 + R2, then R1 + R2, and L1 + R1 + L2 + R2.
Extreme Lap Challenge:
Same as above except enter: L1, L2, L1, R1, L1, R2, L1 + R1 and then L2 + R2.
2x Prize Money:
While you are at the main menu press L1 AND L2 at the same time, then press R1 AND R2 at the same time, and then do L1 and L2 again. You should see a message.
Unlimited Ammo and StarCom Team:
When you are at the team selection screen, press L2, R2, L1, R1, L2 + R2, L1 + R1.
Infinite Shields and Turbos:
To activate this code, go to the main menu and enter the following: L1 + R1, L2 + R2, L1 + L2, R1 + R2. You should see a message...also the code works for only ONE race, you will have to re-enter it.