I have the wood version of the EJF Bobbycat (still in kit form) and it looks really sweet! Yes, balance could definately be an issue with the heavier engine so far back. But, the model is supposed to handle pretty high wing loadings. When I bought the kit I asked about flying weights and was told that up to 6 lbs. would not be a problem. I can't see that model being so heavy but I guess it's possible with a full load of batteries, retracts, 7 - 8 servos, and a glass/paint finish.