Extreme-G 3

Infinite Shields/Boost:
At any point on the title screen, on any controller press (all the way): R, L, Z and repeat this a few times (the timing is a little odd) and you will get a message saying something like:
"P1 Cheat Infinite Shields ON"

It will work for whatever player puts the code in.

This gives you infinite shields and boost power, even in League mode. The other thing you can do is when in League Mode, pause the game and enter the same code. You'll get a similar message, and no matter what happens, when you finish the race, you'll be awarded 1st place and get all the money.