I have two rotarys. They do sound almost the same as a 2c. I like the sound of a pair of four cycles much better. I think the .56 is more than the plane needs. Almost everything flies better when built lighter. Why not try a pair of slightly smaller(lighter) four strokes. I know the 4c won't look as cool on the ground but they will sound much cooler in the air. After all do you want a static display model or a joy to fly.