3D Gamers has a special Grand Prix Legends demo (GPL 2004 Playable Demo) that is worth getting.  It was created especially for Blackhole Motorsports, and it has all of the Papyrus patches as well as some of the better 3rd party updates for Watkins Glen and the Ford Lotus.  Compare this demo to the original Sierra Demo, and you will see why so many fans are still playing this Glide/D3D/OpenGL game after all these years.  File size is 83 Megabytes.  Here is the URL:

http://www.3dgamers.com/games/grandprixlegends/

Enjoy!