Let me start by saying I'm not sure the data is clear enough to make any broad conclusions about the Surefly Mag on my M20F.  However, I'll post some graphs I made showing LOP TAS and LOP Mpg from before and after installation.  The "before" data are from speed runs from the last 3 years.  The "SF" data are all from this winter.  The power settings were all ~15 LOP except at very low (~6,000') where I needed to be a bit leaner.  The weights and CG aren't necessarily the same, so that may cause p