If you defeat Speed King, Drag King, Grip King and Shadow King (in any order) ALL your cars will get free car repairs.

To enter these codes go to the 'Enter Code' menu which is located by going to 'Options' and then 'Career Mode'. It is advised that you disable 'Auto-Save' option as some of these codes can only be used once and you may want to revert the game back to it's original setting.

Unlock Everything in the Game:
Enter the password 'UNLOCKALLTHINGS' to unlock ALL maps, cars etc.

Unlock ALL Bonuses:
Enter the password 'MASTERCODE' to unlock ALL the bonuses in Career mode.

Unlock Chevelle SS:
Enter the code 'HORSEPOWER' to unlock the Chevelle SS in Career mode.

Unlock Audi TT 3.8 Quattro:
Enter the code 'ITSABOUTYOU' to unlock the Audi TT 3.8 Quattro in Career mode.

Unlock Coke Zero Volkswagen Golf GTI:
Enter the code 'ZEROZEROZERO' to unlock the Coke Zero Volkswagen Golf GTI In Career mode.

Unlock Mitsubishi Lancer Evolution:
Enter the code 'MITSUBISHIGOFAR' to unlock the Mitsubishi Lancer Evolution in Career mode.

Unlock Energizer Lithium Dodge Viper SRT10:
Enter the code 'WORLDSLLONGESTLASTING' to unlock the Energizer Lithium Dodge Viper SRT10 in Career mode.

Unlock Castrol Syntec Decal:
Enter the code 'CASTROLSYNTEC' to unlock the Castrol Syntec decal in Vinyls.

Unlock Energizer Lithium Decal:
Enter the code 'ENERGIZERLITHIUM' to unlock the Energizer Lithium decal in Vinyls.

Unlock Extra $2,000:
Enter the code '1MA9X99' to get an extra $2,000 in Career mode (this password can only be used once).

Unlock Extra $4,000:
Enter the code 'W2iOLLO1' to get an extra $4,000 in Career mode (this password can only be used once).

Unlock Extra $8,000:
Enter the code 'L1iS97A1' to get an extra $8,000 in Career mode (this password can only be used once).

Unlock Extra $10,000:
Enter the code 'CASHMONEY', 'REGGAME' or '1Mi9K7E1' to get an extra $10,000 in Career mode (this password can only be used once).

Unlock 5 Free Repair Markers:
Enter the password 'SAFETYNET' to get 5 free repair markers in Career mode (this password can only be used once).