Classic bonuses:
Enter TheGoodStuff as a case-sensitive driver name to unlock the 
classic tracks, Saab 93 TI6, Opel Astra, Ford Focus Rallycross, 
Citroen Xsara, Metro 6R4, Peugeot 205, 
Audi Quattro, and Lanca Delta 54. 

Expert bonuses:
Enter WheelToWheel as a case-sensitive driver name to unlock 
the expert tracks, Saab 93 TI6, Opel Astra, Ford Focus Rallycross, 
Citroen Xsara, Mitsubishi Lancer Evo 65, Subaru Impreza Hill, Lanca 
Delta Integrale, and Nissan Skyline.
 

Downhill bonuses:
Enter Geronimo as a case-sensitive driver name to unlock the downhill 
tracks, Peugeot 405 HC, Audi Quattro S1 HC, Suzuki Grand Vitara PP 
Special, and Toyota Tacoma HC. 


Endurance bonuses:
Enter TheLongHaul as a case-sensitive driver name to unlock the endurance 
tracks, Deerpark GP, Peugeot 405 HC, Audi Quattro S1 HC, Suzuki Grand Vitara 
PP Special, and Toyota Tacoma HC.
 
Unlimited bonuses:
Enter NoHoldsBarred or NoHoldingBack as a case-sensitive driver name to unlock 
all Unlimited bonuse

Submitted by WARRIORX8 and unknown