Mike, the 30 to 40% gap that used to exist between 2 and 4 stroke engines of similar size has nearly disappeared as of late though some are still clinging to that thought. Brands were not part of your question so I'll not comment on that. As far as the chart goes, there may be too many variables to make one useful. There is plenty of info around RCU about what guys are using on what planes and how they fly.