5,000,000,000 Cash And All Tracks Plus All Cars:

Go to carrer, then type in mudeater. You will get 5 Million and it will unlock all 
tracks and bonus cars.

Desert 8 track:
Win the Semi-Pro Championship and Pro Stock Championship in career mode to 
unlock the Desert 8 track. This is a figure-eight shaped track used for a 25 lap 
race.