So... for my top end I decided to go a different route a hobbit DR kit. I’ve seen this kit on a QT50 some where on the inter-webs. Since the QT50 and the Sting are very similar in motor parts I figured why not give it a try. I had to drill out the holes for the studs because the sting has closer studs. I also had to space the kit out from the case 3mm for the ports to line up at BDC. I also ported like a derbi Metrakit.