Bonus Modes
To access the bonus modes you must meet the following criteria:
Mode B -- Get a Bronze Medal or better on every track of mode C
Mode A -- Get a Bronze Medal or better on every track of mode B
Mode AA -- Get a Bronze Medal or better on every track of mode A
Better Weapons, Extra Points, and Class Advancement
Win a medal on each level in class C, B, or A and you get better weapons, extra points, and class advancement in B, A, or AA.
Turbo Start
Right before starting the race, press the Gas button when the last light is about to turn green. If you are playing one player mode and seem to have a hard time starting off, rev the engine until it gets close to 5. Once it starts you off, you should get a faster start.