Re: Engine advice needed
From what little I know of the newer Whizzers, I would pick it up over a 66cc china girl any day. You need to spend time and $ modding a china girl anyway to make them reliable-ish, so I would start with a better base like the Whizzer in a heartbeat.
I assume you will be using pretty much everything off the donor bike except the frame, right? If so, that seems like a great place to start.