All racers
At the title screen, press R2(3), L1, Triangle, L2(3), R1, Square to unlock all characters.

Ending bonuses:
Successfully complete the game to unlock the Free Run mode (no vehicles on the road), Free Run Twin mode (two player Free Run), and Credits options.

Face Off option:
Successfully complete championship mode once to unlock Face Off 1 against the Roadster.

Roadster:
Defeat the Roadster in Face Off 1 to unlock it and Face Off 2 against another car.

Towtruck:
Play in championship mode until you unlock Face Off 2 in the special options screen. Defeat the Towtruck once to unlock it.

Saloon GT:
Defeat the Saloon GT in Face Off 3.

Bus:
Defeat the bus in Face Off 4.

Hint: Increase boost:
Drive on the wrong side of the road to keep increasing your boost. This can also be done by driving in the center of a double lane.

Hint: Full bonus:
Drive a perfect lap (a lap without any accidents) and your bonus will be automatically filled.

Hint: Crash horn:
Hold Circle to use the horn while driving. When you crash, the horn will remain on.

Hint: Quick start:
Accelerate immediately before the "1" fades during the pre-race countdown to start with a slight boost in speed.

Hint: Better turns:
When turning sharp corners, lightly tap the gas to turn sharper and slide less.

Hint: Rush Hour: Boost:
On Rush Hour, you can drive on the wrong side of the road to keep your boost up. If you are good enough, you can use a non-stop turbo throughout the entire course.

Glitch: Sinking taxi:
On Interstate, on the second to last bend you will see a taxi waiting. Crash into it, and if done correctly, it will sink into the ground.