Unfortunately, they are louder, but not terribly so. You can control the noise a bit with the throttle so I don't think it will be too much of an issue, even in my area. And again, they're not terrible, you can still put around when you want to be quiet. It does change the attitude of the bikes a bit, they feel a bit scrappier. We had a blast rolling them around.
Power wise, each of the mods adds a bit more edge to the bike and combined add up to a nice level of performance. These are very well balanced bikes now, not at all tempermental, but certainly more power than the out of the box rides. They feel less toyish and more like real transportation, you can go places. We were cruising comfortably at 30 MPH.
As Pat said, the pipes did not fit out of the box, but Pat laser cut some real nice stainless flanges, so it was not a big deal to modify. The last thing you want to do is modify a brand new part, but the benefit was that I was able to fit the pipe perfectly to my bike. It tucks up sweet and has plenty of clearance all around. I'll post some closeup's later for all to see.
Now, about that ignition timing...
Rich