Ultimate engines are made by the prestigious O.S. and Novarossi brands. The characteristics of these engine adds to the Ultimate line all the best possible features you can have in a nitro engine, specifically power, performance and tuneability. Choose from the silky smooth square stroke of the M3T/M3X or the maximum torque of the long stroke M3S/M3R, but if you are looking for a great engine on a budget the M5 tuned will surpass all expectations.