Let's answer all of your questions Mike.
Loudness? What we've done is trim 3 inches off the internal tube of the muffler. It's not that much louder than stock, if anything we can't notice a difference in the DB level.
Does it get in the way of pedaling? I honestly can say it doesn't. If you look at the video of the San Jose Race. The guys in the front of the race are running the pipe.
It weighs around 3-4 lbs.
If you get one, you won't regret it. Pipelyne has been making pipes for decades and the quality is top notch.