I was leaning towards keeping the outward appearance "old school", but I found this Yoshimura slip on and was able to get it for $130 to my door. It's a $400 pipe and the dyno graphs show (presumably) big increases over stock. I figured that, along with the pods, jetting and some dyno tuning and I ought to be able to get to 100HP vs. the 94HP Suzuki claimed. And it would probably be easier to tune for this pipe vs. some cobbled together system. No matter, it ought to be a good bit more than the 49HP that the GS550 was rated!