First I will try and answer Mikes question and really it boils down to the fact that back when I was building, the factory was advertising more speed with the speed options as well as the better role rate. Along with this is the fact that I like the looks of the shorter wing much better. This is just a personal preference. If you look close many of you will notice that I have the dihedral built into the wing instead of the flater speedster wing, as I wanted the stability that this provides. So I have the short wing with the stability. Mike I can not really answer much about how mine compares to others as I have only flown two other foxes. A IV without the speed mods, and a true model IV speedster. By this I mean that it had the speedster tail and mine does not have the better vertical as my kit was built prior to this being available. Mine is a little faster in cruise and the true speedster with the better tail was better with the yaw. All three have the 912UL.