The Feigao will fit within the stock gearbox. Not many people are running gearboxes anymore. Any of the lighweight brushless motors will work, just need to figure out how to mount them. I went the easy way and got the GWS 2208 motor and the GWS 15amp brushless speed control as a combo. Then bought the GWS stick mount. The motor attaches to the stock motor stick that came with the kit. You will need to upgrade your batteries too. 1000ma 2s batteries work well. You can hollow out the battery compartment and fit in a 3s if it is not too big. Match your prop to your engine so that you don't fry everything.