Bassani Prostreets are a real nice performing set of pipes. We tested them on a few combos last January in 95, 103, 107, and 114 builds. Great scavenging, especially on the 103 engines and up. Some of the best numbers for 2 to 2 pipes. Now Syclone has good info in that for stock or mild builds, the Prostreets will OVER - scavenge, especially if you don't have the capacity to do front and rear cylinder trim, but they are still pretty tasty if you have tuner that knows how to use the SERT for EFI bikes. If you can't find a good tuner, they will throw their hands in the air and send you on your way with TQ dip, because they can be a bit of a chore to tune with stock heads and cam. And Grayrider touched on one of the reasons for why they perform well. Too many exhaust companies are forgetting the physics & engineering of performance exhaust and are concentrating on looks. There is a lot to making good pipes, too much to get into here.
Want another suggestion for great performance and easy on the wallet?.......... good ol' Cycle Shack M series slip ons with stock header pipes. Easily tuneable and cheaper than the overpriced SE slip ons. Nice finish and great sound.