got mine in 2011 at Sturgis, did the stage 1 and it runs and sounds great, has some rumble but not too loud, all a matter of what you like. I've seen it posted before and thought it a good suggestion, next time you are on a poker run or at a bike night take note of the different exhaust.
They do sound good, definately get louder the more miles ya put on em! 20K on mine now, if they get much louder gonna have to start thinkin about repackin them.
I have the same setup as Rootro. Got deeper with the cat gutted. Like the sound, but don't love it. I'd prefer louder WITH the deeper. But I'm hard to please. I'm interested in CFR's. The 4" definitely look good. I get a lot of compliments.