Saw it last night and it blew my mind. Obviously the unit roster isn't the best but it gets the point across. I can already see hellions racing around picking up concussive shells, force fields, etc. and maybe even add energy for some nitro and put in energy-stealing powerups and whatnot. The editor really is insane Also there's a DT TPS WIP on Youtube with a unique chopping skill and things, you should check that out too.
There is a similar racing map/mod for SC1. And some people have made it pretty good by SC1 standards. So this idea of a SC race is an old one indeed. But in saying that this SC2 one blows the SC1 out of the water. The SC2 one is really good.
I had no idea that the map editor was this powerful. I wonder if we're going to see a dota for SC2...XD