Thanks for writing....
Id suggest going with the lite-jett. We sell that as standard equipment on the 76L engines and include it with the 60L (hover) engines too. At the lower rpms these engines run at, its not that loud. Best of all it weighs next to nothing. And since it is non-tuned, there is no tendency for a pipe-step - throttle remains linear.
The other two mufflers are tuned devices. For sport, pattern or scale use, these are great when combined with the BSE-76L. I use the turbo-jett on the 76L in my Edge 540T - gives an additional 1000 rpm on the top end with a 14x4 or 14x6, really helps it swing up to a 15x6 if I ask it to, and the midrange is great - lots of torque. But for a profile application, its not the right choice - just not going to fit.
The boxxxer should be awesome with the 76L on it !!
Suggestion..... airframe mount the needle valve. In fact, you can mount it on the tank side of the fuselage if you wish. If you pass the supply line from the needle through the fuselage side right to the carb, it might make the plumbing look nicer when you are done
