Easy money
Note: This trick requires two VMUs. Save the game on both VMUs. Send the cars your acquired from one VMU to the other VMU. Load the game from the VMU with the extra cars. Sell the extra cars for easy money.

Select championship mode, then go to race. Go to "Special 1" and select "Heat Stage 1000". When you finish, you will get paid $5,550. Go to exit, choose to quit the race and repeat

WSK Races
Successfully complete each of the official races and event races to unlock the first ending sequence and WSK Races. The WSK Races are the Front Drive Car Cup, Rear Drive Car Cup and 4 Wheel Drive Car Cup