It took me some time to find an exhaust that I liked. I finally decided on the Two Brothers. A lot had to do with the fact that it was sitting on the shelf at my local CycleGear shop and I could see it in person instead of guessing with pictures on the internet.
It also showed a dyno on the box and website. 4 rear wheel horsepower for a slip-on. I'd say that's around 6 at the crank.
Pretty darn good for a slip-on. Brings me to 130 at the crank.
Install was a pain because it's an undertail and I had to remove EVERYTHING.
Even my kitchen sink. Although I didn't really understand that part of the instructions
Anyway, the exhaust is LOUD and very very deep and throaty. Not like a lot of other pipes that sound crackly and tinny like a soda can. I've got nothing but compliments on the sound because it is so deep/throaty and beefy sounding.
Two Brothers even makes a baffle for it in case you wanted to tone it down a few decibles.
Anyway, I'm super happy with my choice and the quality of the exhaust.