Mine is fairly quiet. At speed, I can barely hear it over the wind noise. It's a lot quieter than the stuff Jack has been running, Goldies, Dunstalls, etc.
Mine is an Indain one. he English ones I think are a bit louder. They also have removable baffles in them that mine doesn't have. The upswept mufflers are also louder than my EFI. I like the level of noise mine puts out very well, a log way from obnoxious, but loud enough to be heard a block away at a nice low thump. It doesn't seem to disturb anybody, except maybe when I spit traffic up to a stoplight and nail it to get away when the light turns green. It's maybe a bit loud in that canyon! But still a LONG way from any Hardley. For me, it's perfect. And is a reasonably good performer compared the other pipes I've ridden against. There isn't much difference between any of them, but this one is middle of the pack or better. Works for me, nice thump that performs well. the best performing one I've seen is the Dunstall, but unpacked it's pretty loud. Put packing in it and it's about the same as mine.
But there isn't enough difference between them to get in a big battle over. they all do outperform the stock bazooka, though.
Bare