Back in my Uni days a mate had a Suzuki GT750 'Water Bottle', that he used to race on weekends. He was obsessed with expansion chambers and designed/made his own. (I had one ride on it and gave it straight back, it was vicious). Anyway, he had street mufflers that he would slide over the stingers. These were made from (back then) steel Fosters cans. It was just the funniest thing, but then he has a pretty different unit.