It will add more drag and increase addverse yaw. You will get more wing area and be able to fly slower. I would rather clip the wings and turn up the controll throws. Just think of all of the full scale J-3's and Taylorcrafts. There are STC's for clipping the wings not adding to them. On a J-3 they cut 40 in from the inside of each wing. That sure takes the float out of your landings.