"Leo Vince" If anyone can clear up anything on the differences between the motocross and enduro can that isn't stated here please do so. my info is for last years stuff. here is mine on a WR, its a youtube link. the difference between the YZ and the WR slip on was just fittings. and its just your standard race type muffler. a straight thru perforated tube with packing around it. if you run without the rear baffle plug, the exhaust does a real good job of filtering out the high frequencies, but puts out some very satisfying deep base rumble, and still easy on the ear drums. I bought the WR version, the WR muffler comes with a header gasket so that the slip on will fit the WR's smaller 38mm header pipe. and they come with different end caps. which is swappable. I eventually got a YZ header and it slips on without a gasket. . and the WR comes with a smaller diameter rear baffle insert. And it is the quietest. I actually found a larger diameter X3 baffle on ebay and installed it. I think it was left over from a X3 for a CRF450. parts are for the most part interchangeable. I think they have two diameters of X3s. a fat one and a skinny one. Fat one for 450s and skinny ones for smaller bikes. the euro version of the leo website has schematics with dimensions and pictures on the baffles. I found it very helpful.