I own a 2012 WR450 and am in need of a slip on exhaust , 2012 models already have the megabomb header stock so i only need a slip on. Is there anyway of fitting a FMF Factory 4.1 RCT Slip-On on a wr450? if not i will stick with the fmf powercore 4 but from my understanding the factory 4.1 is better? this on fits yz450 and im not sure if they have the same dimensions as a wr, http://www.ebay.com.au/itm/FMF-Factory-4-1-RCT-Slip-On-Exhaust-TI-Carbon-Fiber-For-Yamaha-YZ450F-2011-2013-/380861558455?pt=AU_Motorcycle_Parts_Accessories&hash=item58ad1e2eb7&_uhb=1 im also getting the tuner so what map would be used for the factory 4.1? thanks guys, and i apologise if this question has already been asked but i cant seem to find it!