Each copy of the game comes with a different bonus code. Here's a list of the cheats for each bonus code:

Bonus Code 0976
All Cars: MKCLLB
All Difficulties: WSNXZU
All Parts: FHPCNU
All Tracks: ODIATU
Baja Buggy: NQFIPE
Battle Tank: LHZWOH
Hovercraft: IURUOT
Jet: GOBUUR
RC Cars: WWBDBU
Super Focus: OQJZZY

Bonus Code 1154:
All Cars: WWACNU
All Difficulties: AUNAMA
All Parts: UZVLLB
All Tracks: XWUDBU
Baja Buggy: PHOUOT
Battle Tank: ZIIUUR
Hovercraft: MHXIPE
Jet: LOWWOH
RC Cars: AQVATU
Super Focus: UYNFVA

Bonus Code 1432:
All Cars: FMGUOT
All Difficulties: UXNKFB
All Parts: KEZIPE
All Tracks: RVNUUR
Baja Buggy: VURCNU
Battle Tank: ZSSDBU
Hovercraft: NXDLLB
Jet: YJBATU
RC Cars: GBPWOH
Super Focus: LPGXUE

Bonus Code 1866:
All Cars: OQJHOK
All Parts: FHPIWQ
All Tracks: ODIFCS
Battle Tank: LWXEIF
Jet: RUGSSH
Hovercraft: BKQBAU
RC Cars: PFKCXQ
Super Focus: WSNBSB