one thing to remember with politicians and laws is that they don't give a rats a** about how much force is being transferred to the wheel. if you have a motor that has a higher watt rating than the law says is allowed there is no way you are gonna win your case in court. if you want more speed or torque just get a 200W chain drive or something. either that or do what some guy on youtube did with his motor. he lives in the UK and bought a 500w or 1000w cyclone, i can't remember which, and had some fake stickers made up on that metal foil material they use for manufactured parts. basically it just says his watt rating is 200w so if he gets stopped he's still "within the scope of the law". I doubt a police officer is going to impound your bike and have a specialist run tests just to make sure you are in compliance.