If you enable any of the following cheats you cannot progress any further in the game. If you win a race it will not count.
Hold L1 + L2 + R1 + R2 + R3 (Clicked + Up) + L3 (Clicked + Down) at the main menu. A sound will confirm correct code entry. All bonuses will now be unlocked.
Big Head mode
Press Start to pause game play, then hold L1 + L2 + R1 + R2 + R3 (Clicked + Right) + L3 (Clicked + Left). A sound will confirm correct code entry.
Single player mirror mode
Press Start to pause game play, then hold L1 + L2 + R1 + R2 + L3 (Clicked + Right) + R3 (Clicked + Left). A sound will confirm correct code entry.
Use the following trick for an extra boost that can
help you to victory at the end of a race . When you are coming
up on the finish line, have your boost meter almost all the way
full. When the finish line is fairly close, throw on the boost.
Do not stop holding on the boost and your car will began to heat
up. After the meter is all the way to the end your car will explode,
launching you a good distance forward at an extremely high speed.
To make yourself go faster in any vehicle while driving
(you must let your boost charge), keep tapping X. This
will make any vehicle go faster and not use boost.
When on any track with big or long jumps, hold the
D-pad in any direction and your vehicle should do a flip
in that direction.
At any point on a track, hold R2 + L2
and press Circle. Release Circle and you should
be doing a burnout. This does not work with some vehicles. The
best vehicle is the Rally Car. The best terrain is in the mud.
Note: This was done with controller setup 1.
Easily controlled vehicles
The dirtbike and quad are the two most controllable
vehicles due to their ability to ride along the walls with ease.
Drive in front of an opponent while in mud. Your opponent will be blinded and can crash or go off course.
If you have dust or mud on your windshield you can remove it by flicking [Look around]. You can also remove it by pressing [View Change] twice.
Before a race when you see the front of your car or
bike, notice the banner that reads "Free The Runcorn".
Runcorn is the town in the U.K. where the game was created.
On some races there are big screen on the sides of
the track that show your vehicle racing. However, if you pause
the game in front of one of these screens and rotate the camera,
the screen displays this even though the game is paused.
Strategy guides from GameFAQs