I have a dl50cc and a smoke system. I used a lot of baking soda and ca glue to beef up on the inside of the firewall. I have just added two washers per motor mount, on the left side to give it more right thrust. Before it would make a hard hook to the left. I'm using a 20"X 10" prop. That is the lagest dia. that I can use, and I'm still maxed on the rpm. I used li/po for the engine 7.4 volt and 11.1 for the rec. with voltage regulators. I think I'm still a little tail heavy. I had to added lead to the cowl. When I get it the way I want it, I might move a battery or two under the gas tank. I don't like using lead. It will still fly unlimited vertical with all the extras. Good luck