I have an Enya .53 four-stroke. Powerwise I feel it is quite adequate and flys the plane very scale like. If I wanted the plane to be a faster and more aerobatic I would be looking at putting .50 2-stroke on it or maybe a .70 or .80 four-stroke. I am really happy with the Enya, it pulls very hard but doesent over the power the plane. I don't anticipate ever changing the engine, I think its a perfect match for the plane.