I can tell you, and I hope other PV1 owners feel the same, that the PV1 DEFINITELY quieted down after a few months. I've had mine installed for over a year and it is a LOT quieter than when I had it installed. In fact, at some points I wish it were a little louder... although it doesn't really matter. I love the hum it makes while cruising, and the growl it makes when reving.

Supposedly, the PV2 is a bit more open, so it may be a bit louder than the PV1 brand new, but I have no idea. I'm assuming they probably sound very similar and over time will, too.