Originally Posted by bgoodsoil
Stock muffler is 8.8lbs
I'd be REALLY surprised if the ST's muffler were that light. The thing is pretty solid stainless steel. Either way ... I did a much of measuring and the midpipe from a Kawasaki ZX-10R is exactly the right side for the output of the G/S or GS collector, and the rear collector/crossover from an 85-87 R100/80 bike.
Mated perfectly, and it now weighs ~5 pounds, where my old muffler weighed ~ 9. It's pretty quiet, no acceleration flat spots, and looks right.