I have a WSB style can on my bike, sounds awesome .
it was me and a couple of mates that developed this one and now they sell it as the RaceFit can.
Been stopped a number of times in the odd spot check for speed and number plate etc. To date I've never had any hassle with the can. Thing is to use your common sense .... if you see the law, pull the clutch and coast along. If they follow you, keep the revs below 3 to 4,000.
If your around Derbyshire let me know I'll gladly meet up and let you check it out for looks and sound.