Its not that the Vileside (whoops, bad habit ) teardrop exhausts aren't 'known', its that most of use aren't made of out gold. Even titanium exhausts from the less exclusive Japanese manufactures like Trust are expensive let alone those from companies like Vileside, Amuse, Fujitsubo or god forbid ARC.
Its a shame Rezz didn't continue his little commercial venture as he had access to some of the second tier companies that made titanium exhausts.