I'm looking at getting a replacement muffler for my 2007 WR450F. I have narrowed it down to the XCR or E Series. Anyone comment on either? Also, Will the YZ450F muffler bolt straight up to my header pipe, or do I specifically need to buy a WR450F muffler? The YZ part number is 05-90010 and the WR part number is 05-90020.