I got one on mine, had one on my 636 and thats why I bought one again. They ahve awesome fit and finish, ar emade in texas, and sounded great on my 636.
Same thing for the one on my 10R, fit and finish are just as nice as any other top brand out there, they have great customer service also.
Mine sounds great, on the 10 it is not too loud over stock, had a deep grumble at idle and quick blips of the throttle. I cant tell at high speed cause I am concentrating on controlling the beast when I do go WOT, but one of friends said it sounded really good when I buzzed him at 120 the other day and he had his window down.