This is a Porsche 911 GT2 (Type 993) slot car body. It is designed to be used on the "Scalextric Super Resistant Team GT Lightning" car chassis. Those cars are widely available for around $25.
Approximate scale = 1:32
Note: Printing this model requires supports. I've been using a zig zag pattern with 4.5mm spacing that has given results I'm very happy with.
Much of the credit for this Thing belongs to Rockracer, thanks for the help!
If you print one, please consider posting a make!