The Zenoah will fly it fine if you prop the engine right. Dump the stock exhaust system and contact RCIGN to find out which ones work best. He's likely to say Abell R/C. The GT 80 likes to spin more rpm than most 80's for it to work in it's correct power band.

My Giles has a Brison 105 (6.4) on it so the engine installation won't help much. I'll try to e-mail some pics to you guys since I never can get uploads through to the forums. No, it doesn't weigh 28 pounds, closer to 25-1/2.