About the prop, 11x5, 11x6, and 12x5 will all work then sir? And as far as the hot vs cold plugs... Do either of them work any better in cold outdoor Michigan weather? As for the fuel tank. I might as well replace it. I already got a light Hayes engine mount to replace the stock metal one, and 3" foam wheels to replace the stock rubber ones. The stock tank is 11oz and I hear the Irvine .53 is a fuel sipper. Can I just get a 10oz and save a tad more weight? It's just that everyone on here ends up adding tail weight to their US40, and I'm trying to just build my front end light instead. - Joe