Extreme G3 cheats and cheat codes for Gamecube

Enter the following codes at the main menu. If the codes are accepted
you will see a message.

Unlock every tracks and teams:
L, L, R, R, Z, Z, L + R + Z. 

Always win 1st place in races in career mode
Press R, L, Z, L, R, Z, R, L, Z.

Unlock Xtreme lap challenge
Press L, R, L, R L, R, Z, L + R.

2x prize money
Press L, R , Z, L, R, Z, L + R.

Infinite shields
Pause the game play and press L + R, Z, L + R, Z.

Infinite ammunition
Go to team selection screen and press L, R, L, R, L + R, Z.

Unlock StarCom team
Finish XG career mode

Open extra Tournaments:
Open the 500G class, finish the Caesium 250G tournament. 
Open the 750G class, finish the Caesium 500G tournament. 
Open the 1000G class, finish the Caesium 750G tournament.