Epsilon Tractor Successfully complete the "Epsilon Tract" mission to unlock the Epsilon Tractor for Michael.
Hot Rod ATV Successfully complete all main storyline missions to unlock the Hot Rod ATV for Trevor.
Spawn Stunt Plane (fixed-wing stunt plane) While playing the game, quickly press Circle, Right, L1, L2, Left, R1, L1(2), Left(2), X, Triangle.
Spawn Trashmaster (garbage truck) While playing the game, quickly press Circle, R1, Circle, R1, Left(2), R1, L1, Circle, Right.
Spawn Rapid GT (two door sports car) While playing the game, quickly press R2, L1, Circle, Right, L1, R1, Right, Left, Circle, R2.