A year ago someone already mentioned this ultra-light mid drive RC kit: http://www.gngebike.com/ultralight-300w-kit
At the time, it seemed to be sold out / unvailable. Anyone tried it ? Doesn't seem to be GNG produced, as there are other offers on taobao.
The price tag is quite nifty for only 300W, but the motor seems intersting. My concern would be noise and gearing durability: the motor orientation suggest a bevel gear, which is noisy under speed, and tend to brake fast under high torque (that's actually the main issue with crankshaft bicycle drive IIRC). Any thoughts on that ?