Type in the codes in the Secret Codes menu in career mode:

mastercode               Unlock everything
unlockallthings          Unlock everything

safetynet                5 free repair marker
horsepower               Engine upgrade

Geld (im Karrieremodus)

1MA9X99                  Plus $2.000
W2iOLLO1                 Plus $4.000
L1iS97A1                 Plus $8.000
cashmoney                Plus $10.000
1Mi9K7E1                 Plus $10.000
LEIPZIG                  Plus $10.000
reggame                  Plus $10.000 and a few cars

Autos

cokezero                 VW Coke Zero Golf GTI
onlinesubaru             Subaru Impreza WRX Sti
mitsubishigofar          Mitsubishi Lancer Evolution
zerozerozero             VW Golf GTI
itsaboutyou              Audi TT
worldslongestlasting     Dodge Viper SRT10
unlockallthings          Nissan 240SX, Pontiac GTO, Chevrolet Cobalt SS und getunter Dodge Viper
collectorsed             Acura NSX, Acura Integra, Audi RS4, Lexus IS350, Pontiac Solstice GXP

Parts

energizerlithium         Lithium Energize Vinyl frei
castrolsyntec            Castrol Syntec Vinyl frei