Ok, anyone know what aftermarket silencers will fit on a 2000 WR400F - judging from the OEM diagrams, the headpipe looks identical from 98 to 2007 - the part number is "almost" the same - the long number seems to stay constant, the prefix seems to change yearly, if that doesn't change yearly, it's the first suffix that changes - this is making me think the Headpipe is the same across the board. As for the silencer, 98 to 2003 (which includes 400, 426 and 450's), the can seems to be identical on all, they have changed inserts along the way by the looks of it, BUT the number, once again doesn't change except for the prefix. 2004 and up seems to have changed in the look of the can - probably still the same specs as the 03 though.... I can't see physical fit being a problem here, as for backpressure etc - would there be any sort of change - it seems that you can buy multiple inserts/baffles for most aftermarket pipes and that would mess with all those specs anyways... SOOO, anyone know for sure whether a 2003 450 silencer would work on a 2000 400......it would certainly open things up on Ebay for choices seeing there's almost nothing for 2000's yet a boatload of stuff for the newer bikes... Thanks!