If your going to use the 3g unit the step down is in the 3g controller according to the instructions. I'm running mine stock at ths time just gave her her first real maiden this weekend. Unless your a real experienced pilot set it up stock for now. Then when budget allows get a Castle 100 amp esc and a seperate bec then. That'swhat most of the guys I fly with have done. Take your time setting up the head it's both easier & more difficult at the same time. Some things I learned leave all your ATV setting at 100%. make sure everything is as close to mechanically perfect as possible. This will make things easier after. It's a great flying bird I love the thing. I've got 4 other heli's all flybared and this thing blows them away. I flew my 500right after flying the 550 today and it took almost 2 min to get the feel back. I'm sure you'll like it keep us informed