Enter spiDER at the new game menu. It will say all cars are unlocked.
Make a good barrel roll
To do a good barrel roll on the corkscrew in the movie A Whoopin and A Hollerin go to the left of the ramp(at the end). It should make you roll around in the air a few more times and you should land on your tires.
Nitro at any time
At the "NEW GAME" menu, enter NiTrouS as a drivers name. It is case-sensitive.
Speed Boost
Press R1 when count down is on u get a burst of speed at the start.
Unlock All Cars
Put in ChUmP for a case sensitive driver name.
Unlock All Driving Games, Toys and Cars
Put in BindI (the I is capital) for a case sensitive driver name.
All Cars...