CheatOgre.com: Extreme G-3

Infinite Shields And Turbos
At the "Press Start" screen, press L + R, Z, L + R, Z. If you entered the code correctly, an "Unlimited Energy/Turbo" message will appear. Note: The effects of this code only last for one race and must be re-enabled before the start of the next race.

Infinite Ammunition
At the "Press Start" screen, press L, R, L, R, L + R, Z. If you entered the code correctly, a message will appear.

All Teams And Tracks
At the "Press Start" screen, press L(2), R(2), Z(2), L + R + Z. If you entered the code correctly, a message will appear.

Always Win XG Career Mode Races
At the main menu, press R, L, Z, L, R, Z, R, L, Z. If you entered the code correctly, a message will appear. This allows you to win a race no matter if you quit, lose, or die. Note: This must be enabled at the main menu before every race.

Double Prize Money
At the main menu, press L, R , Z, L, R, Z, L + R. If you entered the code correctly, a message will appear.

Extreme Lap Challenge
At the main menu, press L, R, L, R L, R, Z, L + R. If you entered the code correctly, a message will appear.

StarCom Team
Successfully complete XG career mode to unlock the StarCom team.

Quick Start
To get a jump start when you begin a race, hold Forward during the countdown without pressing Gas. As soon as "Go" appears, hit the accelerator