Enter SWEETAS and BONZER as codes for all cars and all tracks respectively.
Ford Ranger Protruck
Finish 1st in Normal Campaign with a car.
In-game music select
Enter STROOTH as a code.
Nissan Patrol GR
All 1st Place Finishes in Normal Arcade Mode with a car.
Use any car in multiplayer mode
To use any car in multi-player mode, where unlocked or not, select the desired car and press A on one of the other controllers. This can be done for any player.