240 ZX and the Bus
First finish the Bar Area course in or uner 3 minutes and you will get the 240 ZX and the Bus.
Diablo in One Player Mode
First you have to come in first place in all 3 difficulty levels in the Uptown Driveway course. Then you have to come in first place in the new level that appears. Race the Uptown Driveway course in Time Trial where you will find a parked Diablo. Pull up the the car and a message will appear saying that you found the car.
Porsche in One Player Mode
First you have to come in first place in all 3 difficulty levels in the Sevel Tight Corners course. Next race the same course in Time Trial mode and go to the hotel. You should see a parked Porsche.
Truck and the McClaren
Finish the Pikes Peak Hill Climb course in or under 2 minutes 30 seconds and you should get the Truck and the McClaren. These vehicles can only be driven in Time Trial Mode.
Soccer Ball Trick
Go into the course editor. While holding the X button, press Triangle to make your cone white. Place the white cone on the course then repeat this until you've run out of cones. Now choose your car and start the race. The white cones will have turned into soccer balls, which you can run into with your car
Go to the car select in 1P mode and go to garage A. Hold Circle while pressing X. Notice that car A03 the Convertible now has it's top down. Go to garage B and do the same thing. Now, car B04 has streamlined headlights and 6 new colors to choose from. Go to garage C and do the same as you did for A and B. Now, car C06 now has a sun roof.
This trick works in 1 Player, Time Trial, or the Course Editor modes. To enable these cars, go to the Car Select menu. Move your cursor to "Garage A" then hold L1 and press Circle. Now move down to "Garage B" then hold L1 and press Circle again. To finish, move down to "Garage C" then hold L1 R1 and press Circle once again.
Note: These cars are temporary and cannot be saved.
While in any garage, hold L1 and press R1 to turn on a cars blinkers.