During a race pause the game and to Race Statistics. Now press R1 R2 L1 L2 and you'll hear an engine roar if done correctly. Continue the race and press Triangle to shoot paintballs.
Drive the EA Sports Car
Go to the Kenny Wallace car and hold X and press Up Down. Continue to hold X until the race starts.
Drive the Pinnacle Car
Go to Bobby Labonte and hold X and press Up Down. Continue to hold X until the race starts.
At the Options screen hold Circle and quickly press Up Left Down Right. You'll hear the announcer say "Go Bobby Go Go Go". Turbo Mode On should then appear in the lower right corner of the screen.