i have both cars the DO Pro is based off the ultra lx buggy and the sprint is based off the hyper 8.5 and both are pretty much buggies but the main differences in the oval cars versus the buggys is the latemodel car has a spool in the center not a diff. and shortr shocks. the sprint is just a buggy with a cage on it. I run RB .21's in them both and hand out some woopins. good luck on our choice. btw ofna is great cuz parts are cheap too.