I lived in Montreal from 1996-2002 and every season everyone said the cops were starting to do decibel checks on bikes. Never heard of anyone actually getting a ticket other than from guys who liked to get attention by talking about what happened to his brother's girlfriend's friend one time last year. I wouldn't be too worried, though the remote possibility is there. I wouldn't do anything like redline the bike near a cop, though.

As for the power question, I have not tried that on a Superhawk. However, I did put a K&N and a dynojet kit on a Ninja with stock exhaust. I found that it had much better top end power. More importantly, it pulled to the redline more quickly. Stock, it was a bit lean, so struggled above 7000 rpm, being fuel starved. It always seemed to run out of pull before it got anywhere near the redline. With the K&N and rejetting, I had more problems bouncing off the rev limiter, as the engine built power much better and was still getting stronger when it hit the top.