Lose the trailer
If you drive the American LaFrance Firetruck down an alley near the Tower of London, you will lose the trailer with the ladder.
Go into Windows Explorer and go to Program Files directory and then Microsoft Games then go into players delete every file except players.dir,sf and london then you will have all the cars and paint jobs. NOTE: This will delete the missions yu've done, so back it up. You do this at your OWN risk. If you damage it, you're on your own.
You need to be driving a police car in any level in Cruise. Press the "Y" key to bring up the screen. Type in SUPER SPEED and press the Enter key. You will go double the speed of the police car!