Long story short, my boat is the only jetboat around here, and is way, way louder than anything else around here. People have come over to the house to complain about it.
 I saw a video on youtube with what appears to be 4" PVC 90 degree elbows clamped on to the exhaust tips, pointed down. They appear to quiet the boat down a great deal. Anybody ever do this? I am a plumber, and have everything to do this, and they would be super east to remove for the times I want the boat loud. I don't think they would create any backpressure, other than when the boat is idleing and the tips were totally under water. Seems like a cheap, and easy way to quiet down the boat, and keep peace on the lake. Also, the D.N.R. are really dinks about things like loud boats around here, so it may keep them off my butt too.