Thought I'd share my Dad and my winter project. Dad picked up two different styles of 3D printed sprints from a really talented dude named Woodguy over on Shapeways. We went with H&R Jackrabbit 14K motors, 9/27 gearing, H&R guides and learned how to make my own tires cast from model car "modifieds" tires on H&R or Pro-Track wheels.
Close ups of the two bodies styles that were available at the time
Running them at 12V and doing 3.1 second avg lap on my 4-lane 7' x 16' routed oval Long Creek Speedway. They shine on the inside lane, and you real have to "handle" them on the outside lane. I recently started to switch from silicone to Urethane tires and I don't have alot of rubberlaid down yet. Fairly stable cars, but when they crash, its pretty realistic...
More pics to come