I like the mufflers on the Fox 15, as it gives your hand a firm gripping area for a better hurl! Actually a much more user friendly engine for the Akromaster is an OS, Magnum, or Thunder Tiger .10 , as these have plenty of power, light weight, use common fuels(and not much of it!), and fly a light Akromaster just fine. I actually have a Supertiger X-11 on mine right now and it has PLENTY of power, but they are somewhat hard to come by.