I had people comment, positively, on the stock, whispering sewing machine sound. It still backfired some & I liked that. Now, with the supertrapp, it rumbles & spits. I like it more than stock, by far.

I haven't gotten around to putting my screamin eagle pipe on yet, but I did drill 3 decently good sized holes into the end of the muffler and that really changed the sound and let a lot more flow out. Now it sounds awesome on deceleration. My Dad put his screamin eagle pipe on and HOLY crap its so freaking loud that its hard to be around. He jammed a bunch of baffling up in there to make it a little more quiet. It worked but now I doubt he gets much over stock performance out of it. He quieted it WAY down, I'm not going to do that near as much. Loud pipes save lives, and I've seen it first hand do just that.

I had mixed comments when my pipes were stock.  People appreciated the quietness, but other bikers said it wasn't safe to have a motorcycle so quiet.  They said it's bad enough that people can't see us, but at least with a loud pipe they can hear you.  I completely agreed with them and that's why I put on an aftermarket pipe.  It's not loud in lower gear/rpm, but when I open it up I'll draw attention.  I didn't want a REALLY loud pipe because I think that's excessive on a person's hearing ... especially the rider!

I dont know how much they actually save lives, but from a logical standpoint you can't deny the claim that something that makes more noise will get more attention than something that makes less.  Look at the Prius controversy...those things are so quiet at certain speeds that the Blind community is pushing for noisemakers and just the other week some kid got injured when he got hit by a Prius he didn't see.  

quiet bikes have almost no exhaust sounds when they approach from behind. I've driven cars in LA and been stuck on the freeway.  When lanesplitting past you, you can hear a harley a car or two back.  You notice crotch rocket abouts a quarter of a second after you hear "vwwoomm" go by your window, ten inches from your head.  (Common reaction is usually a   and some choice words)

PS- low frequency sounds travel farther than high ones.

"Loud Pipes Annoy Registered Voters"

I'll stick to a viz-vest to get noticed.  Then ride like I'm invisible.

I want my bike quiet enough to avoid complaints from the neighbors when I head out (or return) in the wee dark hours.

I want to preserve what is left of my hearing.

But I also want it to sound like a motorcycle when I crank open the throttle!