I recently put on the stock YZ muffler on my 2000 WR400. It's amazingly light, but certainly a bit louder than the uncorked anchor of a muffler that comes on the WR. I am seeing increased attention to DB testing at rides I attend. Does anyone know of a quiet LIGHT muffler for the WR, that is spark arrested? The new FMF Q-Power (quiet power) is apparently just as heavy as the stock WR muffler. (unless the salesman didn't know what he was talking about). chris.