The edit is by Swine.  I just messed with the physics to get it to 3wheel.  
Its not perfect but should be fun to play with and this one will work online.
Also, the zip comes with some setups to start with as a base, but I am sure
they can be improved.  Also, included is a 2003 Dennis Erb Jr and 2004 DW skin. 

To change your Xtreme skin to 3 wheel . Open the skins .str file with notepad and change
the top lime to car = 3wheel.
