Modding

From TurboSlidersWiki

Modifying Turbo Sliders

Almost everything can be modified by text or image files but note that if you make new cars or modify existing tracks or terrains, this can cause problems with network games if all players do not have the same modifications. You will also break your old existing track records if you make significant modifications to existing tracks or cars. (You can, however, change graphics and sounds etc.)

To learn how to make total conversions, read README-totalmod.txt.