Well, when I bought my Avid MKIV, the wings were built wrong, but I figured  for the price I paid, I could afford to buy some Kitfox parts and build KF wings to fit it. I've found that there are several issues that need to be addressed to make this work though.   The first issues were pretty easy to deal with:   Lift strut attachment - The KF spar brackets are all made to accept rod end bearings instead of the wider end of the strut tubing that the Avid has. I figured that the easiest solution is to just weld threaded fittings into the ends of the struts.   Flaperon location - Because the flaperons hang on the KF wings differently, they end up in a different spot relative to the support bearing on the fuselage. No problem, just modify the support bearing and linkages as needed.   Then the bigger issues:   Wing incidence and wing folding - Because of the differences in the KF airfoil and the Avid, the mounting points at the fuselage position the spars differently between the two planes. On the avid, the front spar carry through is about 1.4" lower than the rear (using the lower longeron as a reference for level). You could adjust the angle quite a bit by modifying the height of the tubes that the spar pins go through. Even if you do that though, the best I can get is about 1.7° more negative than what the KF has. Also, it appears that the flaperons will just barely clear the turtle deck when folding the wings. You could adjust it to get more clearance for the flaperons to be safe, but this would make the incidence angle even worse.   Has anyone dealt with this before? Larry, I know you had a friend that did this. Any info on what he did?   I'm thinking the only way to do this right is some pretty extensive cutting and welding...   Thanks, Luke D.