On the electric powered warbird there is no exhaust noise, but the airframe generates a considerable slipstream roar along with the prop rip of the larger props. I have a Benedini Merlin sound system that works ok and with 4 car stereo speakers the engine noise is very realistic at speeds below about 70 mph. If some one launches a chain saw motor it will drown out the Benedini sounds but they still can't catch the electric powered Mustang. I have a 20-30 mph speed advantage over IC powered models and nothing will touch it in a vertical climb so far, not even a couple of sport jets that tried. When I do a high speed low pass then pull it vertical it will just fly straight up until it is too hard to see. And the 4 blade prop is the fastest, and most efficent prop I have used. I usually do vertical rolls to slow it down some.