Is there much of a weight difference between a stock YZ and a WR exhaust. I ride with an 04 WR uncorked. I also have a Pro Moto Billet insert in case I ride somewhere that requires 96db. Not to thrilled with the performance of the insert. I even drilled a few extra holes in it to open it up a little more. Didn't help much. It sucks riding with it. I must ride in different areas of Utah than you guys. I've talked with BLM rangers out on the trails and they never said a word about the noise. What I thought most of the environmental groups are offended by, is off-roaders riding in WSA's or wetlands. Not to mention the oil and gas exploration planned for primitive or archaeological areas.