a 3 rd channel remote mixture conrtol is the way to go as atleast you can run the engine rich in the water and slowly lean it out alittle to get maximum rpm,s . buy your self something like a Garmin GPS , i just grabbed one off ebay for $50 near new., very accurate speeds recorded too. don,t go high on the nitro unless your going to add head shims as if you don,t you will damage the piston crown and head button from detonation, 25% is enough. and that muffler is what you call a box muffler, toss it as there rubbish unless your doing a scale boat. have a look around for a good tuned pipe and header to suit.