I've got the Su-31 (which is really an Su-26, which I think is sexier) with a Magnum XL 70 RFS 4 stroke. The magnum is a beast and probably more power than it needs, but it should be fun. I have yet to fly it, but I can comment on the build and quality. I have one of the much later versions bought a few months ago. They have nixed the lead plate, and cut down on some of the structure in the fuselage. It looks kinda flimsy, but it really isn't. The high stress areas have actual birch plywood, while the rest of the plane is 2 or 3 ply laminated balsa. I haven't weighed mine, but I am sure the magnum will haul it around just fine. The build quality is excellent, especially for the price. I did some taxi tests today, but didn't fly because the Kansas winds were just too crappy (flipped my Skyraider II on landing), but it has good ground handling manners and wanted to get airborne after about 70 ft at 1/2 throttle. The covering is excellent, and for the price, it can't be beat. I don't expect a 3D plane cause I am just not into that thing, but I have heard that it can be as aggressive a sport flyer as you can handle. As for the instructions, toss them. The CG is off, and it really doesn't explain much. I have had enough experience to know how to put one of these things together that it didn't bother me one bit. The control horns in mine seemed okay, but the screws were weak and I replaced about 50% of them due to stripping the heads. Mine also had metal pushrods in nylon tubes, much better than previous versions. I hope it flies as well as it looks and as well as its built. I get comments every time I take it out about how good it looks (even though I don't fly it cause the winds are sucky).