[TeeTee]

The can may be held to the header with bolts but the can itself with the baffles inside is usually welded. There has been a couple of articles where the cans are cut open and the baffles modified but in general it's more trouble than it's worth. And just poking a hole down the can with a drill or rod usually makes it sound terrible.

I've heard of dealers selling the aftermarket cans off the used bikes with your stock old can being used as a trade in. Helps the guy that buys the used bike decide he needs to spend more money at that dealer getting a can for it. Cheating? You betcha