I've recently fitted a Cyclotricity mid-drive E-assist kit to my Surly Disc Trucker. I'm really pleased with it. I do have the throttle fitted (I know it's not road-legal in the UK) and find it handy if I need to accellerate quickly, like on a roundabout, or for the rare hill (I live in West Norfolk!). I have the codes to deregulate it from 250W to 500W. Apart from the legal issues, would I actually notice much difference? How much would it affect my range (currently about 30 miles)? I mostly use the lowest assist setting unless I'm fighting a Fenland headwind. I suppose I'm asking is it worth breaking the law for? Most of the people I know using e-bikes are using 500 or 1000W motors.