HINTS
Play at Night
Hold N while the game is loading to play your favorite day levels at night.

Remove Invisible Walls
Start the race on either Mediterraneo or Mystic Peaks as the McLaren F1 in simulation mode. At any time during the race, drive in reverse, and your horn blaring nd hit any moveable object {not a sign} at about 60 MPH. Now the cheat is enabled. To use the cheat you must drive over 80 MPH and hit any guard rail or such thing and you will go off the track!

Slippery Roads
For a greater challenge, type "SLIP" at the car selection screen.