I have this plane. I first flew it with a Saito 65 and two old battery packs taped together for weight behind the cowl. This is a tail heavy plane. I also added a couple of ounces to the firewall. It flew decent but really didn't have alot of power. I now have a Magnum 91 four stroke in. Plenty of power, flies great. I was then able to take the couple of ounces off of the firewall but had to leave the two extra batteries in for weight. Balance it at the rear of the recommended cg. I had it towards the front of the cg range at first and it would do a nasty tip stall and snap on landing. Now when it stalls it just drops without dropping the wing. Make sure you have plenty of speed on landing. This thing like to land fast. Good luck.
Sam