What are the fastest car parts that you offer?

Not an easy answer. The fastest car will be one built to run on your track you race. A car built for metal tracks, sometimes too fragile to race on old wooden tracks. Car built for wood tracks, leaves behind performance if raced on metal tracks. I have written a very in depth racing theory. If you text me, I will probably cut and paste a lot out of the article. Here is the long answer. Ultimate Guide: How to Build a Winning Pinewood Derby Car