DON'T BUY ANOTHER WING! you can do much more than take the dihedral out, and buying a new wing don't solve them 3 gallons is not much, so stick with her for another gallon or so. then, you you want performance, here's what you do. First, replace the fcontrol surfaces with bigger ones. this is not difficult. your local hobby shop will have hinges and aileron stock (which is what you use for your elevator and rudder as well). get the ones that do not twist as easily. those are usually the tighter grained ones. they are bade of balsa. so are the ones on your planes. if your ailerons are 1 inch stock, replace them with 2 inch stock. you can taper cut the edges and you will never know. same with your elevator and rudder. covering is also easy. 3 practice tries and i was able to do it. also, if you want to cut the tips off yout rudder and elevator you can make the tips part of the control surface for extra kick. The next step is to take a bandsaw to your wing. find out how much dihedral your wing has, and set the bandsaw to half that so you can lay one wing half flat, and it will cut through the center, leaving an equal half the dihedral on both sides. then, set your bandsaw's cutting angle to zero again. lay your wing flat, and cut it on both sides. voila, no dihedral. if you want to drill a hole through the glued in wingspar, you can put in a carbon fiber or aluminum wing tube. you can make it removable that way, but if you want, you can just glue the tube inside. it will be stronger than your previous spar. convert your wing to bolt-on if it already is not. you will have a pretty good flying plane. it will have a lot of control, it will stay where you put it, and it will respond a lot crisper to control imputs, as well as not get so mushy at landing speed.