I'm still flying my Skybolt nearly every weekend. Mine, powered by an OS 91 S2, has more than enough power for anything I want to do. My question is, why would you want to take a 7 lb airplane and turn it into a 10 lb airplane? Mine, swinging an APC 13.5X9, has roughly 2" of ground clearance. A Saito 1.00 would be about as large an engine as I would recommend.