Use Same Vehicles In System Link:
By default the game does not let you choose the same vehicles when racing on a 
LAN. To remedy this, all players must hold down the Y button before selecting the 
vehicle selection screen.

Unlock Tache Telpan XSU-K0cc Racer:
At Vehicle selection screen hold R + L triggers and press black, white, X, X, Y, and 
release R + L. If you entered the code correctly, you will hear the sound of a jet 
taking off.