Cheat Codes
To enter the cheats go to the main menu screen. There are four options (Championship, Versus, Setup, Credits).
Imagine these options are numbered 0 to 3. Input the following sequence (by pressing the Z trigger) while positioning the menu cursor (via Control Stick) at the appropriate menu items. If you mess up you can enter a menu item and return to the main menu to reset.
Alternate Credits: 2, 2, 0, 1
Open All Cars: 3, 3, 1, 3, 2, 0, 0, 0, 1
Open Normal Cars: 3, 0, 0, 1
Open Bonus Car 1: 3, 1, 2, 0, 1, 1
Open Bonus Car 2: 0, 3, 1, 2, 1, 0, 2, 3
Open Bonus Car 3: 1, 1, 0, 3, 0, 1, 0, 3, 2, 1, 2
Open Season 4: 1, 0, 0, 3, 2, 2, 0
Open Season 5: 2, 0, 3, 1, 1, 2, 0, 1, 3, 0
Open Season 6: 3, 2, 1, 0, 0, 3, 0, 1, 2, 0, 3, 2, 2
You should get a smiley face with a rev sound if you did it right.
Extra Money and Power-ups in Championship Mode
In championship mode, the amount of money you have and the number of upgrades your car has is saved into the game's memory but each time you start the game you get to chose your car. This means that there's a simple way to get more money and power ups on a championship game.
Every time you buy a new car, race one race with it then sell it and buy the worst car available. Now buy full upgrades for that car and start another race. As soon as this race begins press Start and chose EXIT to return to the main menu.
Start the championship game again and chose the best car available (it should be the one you have bought and sold). You now have full upgrades for this car and loads of spare cash -- probably enough to buy the next car.
This cheat works even better in multiplayer as only one player has to buy a car for all of the players to be able to select it.
Bonus Track...