I live in Oregon where there are some pretty steep, muddy, slick hill climbs. After doing my research on this sight I went with the gnarly pipe and havn't looked back. It is amazing what it did for the bike!! My 04' 220 just tractors up those hills....I just have to worry about hanging on!!
I noticed a huge difference too. The KDX is a good bottom-end power bike as it is, but the FMF adds top end and helps the low too. Changes your style of riding alltogether!
How did yours fit? I had to heat mine and bend it some. Lots of people complain about that problem. Did yours fit out of the box?
I didn't have any fitment issues with my Desert. The trick was to take everything loose and tighten as you go. I really love the desert pipe. Boosted the low and mid, and it will actually rev out up top now. Does great here (lots of slick hills, rocks, roots, etc). It's great to see the other gents on MX bikes struggling up the hills, while my little KDX just tractors up the hills (as long as I don't fall off though)!
I loosened everything and tightened as I went with the rev pipe. I still had to drill the mounting hole in my silencer bigger so I could move it closer to the pipe!!! The pipe came up about 1/2" short!!! You'd think the ding-dongs at FMF would fix this FRICKEN IRRITATING PROBLEM!!!! WHAT THE HE## IS WRONG WITH THOSE PEOPLE!!!??? ARE THEY DEAF, BLIND, STUPID, OR JUST PLAIN DON'T GIVE A DAMN!!!!!!??? THIS PROBLEM HAS BEEN GOING ON FOR YEARS NOW!!!! FIX IT ALREADY!!!!