Was behind a M3 or an M5 (can't remember) and was surprised to see a similar very visible pair of corrugated stamped style mufflers. To be honest, I don't mind the look of them. I would like something louder, with no drone. I would like to hear Long Tubes, HFCs, resonator delete and stock mufflers, but doubt anyone would have such a configuration.
This thread shows BMW aftermarket mufflers with a simiar appearance.
http://www.e90post.com/forums/showthread.php?t=114249