i have these on my VT 5lt and they are terrific, great for the drags as i have a stock exhuast cat back system, with the helmet on your cant really hear your engine very well so with them open its great and sounds like a drag car lol...
they are 2.5inch electronically controlled from the cabin, i have pacey tri-y extractors and 3inch high flow cats with standered cat back
i hardly use em on the street (even tho my mates beg me to open them up) but one day on highway a guy was driving on his mobile phone in his mazda thing with the roof down, so i opened them and floored it past him. it was great.
as far as the law goes ive never had any trouble, as they are a bolt on, you could make up a solid flange so if you get dicked for having them you could remove the controlled butterfly and replace it with the solid flange to block it, in theory in should pass