Pizza you right about the foamies and I do like to make my planes as light as possible. This will be my first 4 stroke and I have selected it based on recommendations for the Funtana. I believe 4 strokes have more torque than 2 strokes and thought that would be the best choice. My other 3D plane, similar size and weight, has an Irvine 53 and will only just prop hang at full throttle. Keep meaning to get a pipe to see if that will improve it.