I'd like to upgrade a 380 motor (a dragonfly 35) to a brushless type. What is the largest/ most powerful option that my bug will take, and what other items will I need for this upgrade? I keep seeing the ems accesory when looking for brushless motors, but do I really need one with a walkera receiver? Isn't the speed control already built in? Oh, and lastly (another subject) why does the reponse time with the controls seem delayed, and how can I speed it up? Any help would be appreciated---Thanks