(From - Aero mods for chumps thread)
Magical numbers of 10-12 degrees.
Here are just visual concepts. (quick tire change time is valid, could use quick release 1/4 turn camlocks or just delete)
Conceptually, there are rear vertical fences that holds the new lexan rear window/fastback at the best low drag angle. Ideally a true tapered boattail is the best but this might be the easiest to fabricate & even easier to test & adjust the back angles. You could also adjust trim edges depending on your track venue.
http://ecomodder.com/forum/attachmen...5&d=1296259422
http://ecomodder.com/forum/attachmen...6&d=1296259422