Zippi, CG was dead on as recommended with the 91fx. It is a great combination. I used thin rods for tail struts to minimize tail weight. Batt pack is also in the middle, so I have room to play with CG. Its easy to put so much additional weight on any airplane, got to be careful. Not sure what the 1.08 weighs. The problem is not when flying, only when there is that unexpected dead stick at lower altitude, a big engine weighing the nose down can make all the differnce! And with a heavy engine overhanging the landing gear, there are stresses on the airframe that its not designed for. So some additional reinforcing work may be in order if you decide to go with a 1.08.[8D]