Win Next Race: 
At the main menu, press L1+R1+L2+R2, L2+R2, R1+R2, 
L1+R1+L2+R2 

StarCom team: 
At the team selection screen, press L2, R2, L1, R1, 
L2 + R2, L1 + R1.

Double prize money: 
At the main menu, press L1, L2, R2, R1, R1+R2, L2+L1.
 
Infinite ammo: 
At the main menu, press L2, R2, L1, R1, L2+R2, L1+R1. 

Extreme Lap Challenge: 
At the main menu, press L1, L2, L1, R1, L1, R2, L1+R1,
L2+R2 

All Tracks: 
At the main menu, press L1, L1, L2, L2, R2, R2, R1, 
R1, L1+R1+L2+R2