This plane is designed for a heavy 4-stroke engine and it's strange how they say it takes only a 2-stroke engine. As far as balancing a Thunder Tiger .91 or a YS 110FZ would be perfect at around 38oz. A Evolution .100 2 stroke motor would get close to that and fly this baby like a rocket. This plane sounds better with a 4-stroke though. It sounds like the real thing when you get close to the ground which adds a nice effect that turns heads. I also had some overheating problems I think you need to cut more holes on the bottom. The small opening all the way around the outside back of the cowl doesn't lert air flow good enough in one spot right where the engine is. It vents air around the rear of the cowel in a circular patern. You need to cut some openings around the engine area under the cowel. For nose overs which are inevitable with this plane I reinforced the cowel underside with fiberglass mesh and marine grade epoxy. But on the inside of the cowell so it doesn't look bad. I just hit the underside of the cowel with some black gas proof automotive spray paint when it noses over - usually when I land to the right of the runway in the grassy area.
Mine is still going strong and looking good after 5 years - good plane get's alot of attention at shows.