loud. just wait until you get yelled at by neighbours and cops. I had the gytr shorty on my 05 but change it after a month. also, my bike didn't run as well with it--unless you pony up a few hundred for custom mapping. just my .02.
Looks and sounds awesome. Gotta do something about that fender though. First thing that came off mine. Didn't even have it 24 hours and it was changed. Still trying to decide if I want the HR1 though. Leaning towards yes.