Grand Theft Auto Double Pack

Go to Staunton Island. Head for Bedford Point, and bring a tall vehicle with you, like an Ambulance. Go to the parking lot that is behind some buildings in the projects (it was used in the “Kingdom Come” mission you do for King Courtney). Park your Ambulance next to the wall where the Kuruma is parked. Climb up on top of the ambulance and jump over the wall. On the other side, you’ll see a sign that says “You werent supposed to be able to get here you know”. When you’re ready to exit this area, use the ramp that the programmers (very thoughtfully) put there for you.

To do this cheat simply find a taxi or cabbie and steal it (probably works with the secret red cabbie). Drive up to one of your favorite cars with it. When you are there press and hold down the X button. Get out of the taxi while you are holding X, with Y. Keeping holding X and get inside your favorite car. When your character is in the car waiting, unleash the X button. Make sure you do not unleash the X button while you character is opening the car. Now the game thinks you are inside a taxi, good job.

These are all the vehicles that can be unlocked by completeing certain missions or are only availible during certain missions.