Activate the following cheats by entering the corresponding codes as your profile name:

CHEAT FUNCTION - CHEAT CODE
Supercharger - "MAXPOWER". This will add a supercharger to your Extreme 05 car. It is very fast and difficult to handle.
Expert mode cheats -"PADLOCK". This will use the cheats you discover in Expert mode. You will also unlock the Extreme 05 version of the cars when you complete the campaign in Expert mode.
Ghost car - "SPOOKY"
Display best ghost time during time trials - "AITRIAL"
Overhead camera view - "DOVECAM"
Bonus avatars - "UGLYMUGS"
Reverse controls - "reverse"