I've had a pair of these for a while:
American Custom, The Bullet. At the same time I bought the "Mid Rumble" baffles. I bought the American Custom slip ons because they look completely stock and, are supposed to improve performance with a better sound. They look good...
The quality is just satisfactory. One of the Slip Ons had minor spider web scratches on it, I put it on the bottom, with the heat shield on it you can't tell. The mounting holes for the baffles were cut with a torch and some slag was left around the holes. Easy enough to clean up, so I did. Both are very minor issues so I decided to just live with it.
Installation was easy.
I'm not thrilled with the sound/tone. Without the baffles it's to loud for me. On the highway the droning would drive me nuts (nuttier?). The Mid Rumble baffles do reduce the volume but have a Raspy, Ratty tone to them. I've puttered around a little with the baffles. Each change seems to improve the quality of the sound but I haven't reached the deep baritone "Burble" I'm looking for. One day I may order another set of baffles and start over.
Performance? I don't know. I do believe these pipes are freer flowing than the the factory cat-cans, I'm to lazy to swap back and forth and run seat of the pants tests. I do remember reading, "Louder is not Faster".
When I hear a set of pipes that sound good (to my ear) they are usually from Vance and Hines. I wish V&H made a set that looked like factory.
You and I have very different bikes, I know. Just letting you know my point of view. I hope this has been helpful.
Cheers!
Ferrous