I've had 4 Super Sticks and have only a few suggestions. reinforce the firewall and reinforce the tail before you put the feathers on. If you don't you will get cracks where your pushrods exit the fuse. If you want a inexpensive engine that will perform with this plane I'd suggest the tower 75. Seems to have just as much power as a 91fx juist half the price. Also adjust your CG back an inch farther than the book tells you.