I have two bikes with Bafang 250's and generally i'm happy with them. When i first got one i tried to up the amperage to, i think it was 17 or 18 amps, to turn it into a 350w but got error messages so gave up with that idea. A year later and i am thinking i need more power but not at too much expense, I looked at getting a BBS02 500w but the 750w is same price and anyway money is tight at the moment. So I wondered if i bought a 350w controller(about £80) would it make a noticeable difference as i know the only difference between the 250w and the 350w is the controller. Or should i just make do with what i have until i can afford a BBS02 xxxw.