My 06 came with FMF Ti Q2s installed. I'm just now installing the Neduro 2:1 and noticed something odd regarding the way the FMFs are installed. The metal plate on the midpipe (which the three bolts go through) isn't close to being flush. The nuts thus don't go in more than 2 turns, tightening them down dishes the plate slightly. The midpipe flange basically rests against a metal ring which is flush with the cannister end. I noticed on the stock KTM pipe that there is a machined recess thats actually slightly deeper than the flange on the midpipe .... so the metal plate on the midpipe secures down flush on the cannister. I pulled the outer metal ring out of the FMF (leaving just the thicker inner ring): This ring isn't quite as deep as the recess in the stock KTM pipe. The midpipe flange now goes into the FMF cannister but not as far in as the KTM cannister so the metal plate doesn't seat flush, better than originally but not as good as the OEM. I'm guessing this is "good enough"? I can't imagine I'd want to remove the thicker inner ring from the FMF as then the midpipe would just fall inside (if not mounted). FMF kind of gave me the impression that the outer ring wasn't supplied by them .... so I've no clue why it was installed. There was a lot of gasket sealant around it. Beats me as the original fitment seems really wonky. The original owner was very good mechanically so I'm curious.