I just put a fmf q4 with power bomb header on my sons 07 klx 250s. First off the header and can went on and fit just great , no problems at all. Took about 10 minutes.We did replace the main jet to #128 and pilot jet to#40, also took off the smog stuff and put in the bigger klx snorkle. the bike sounds great ( like a dirt bike should) not to loud,and there is a noticable power increase.We live at sea level but sometimes ride upto 6800 feet (at klone peak in Wash. ) so hope this jetting will work in our broad range of riding.Anyway so far am very happy with our fmf purchase.

 

I like the looks of the fmf too. A riding buddy has the full system on his bike.

 

Well done! I'm very happy with my Q4. I actually got to hear it today. It was 60 degrees out , so I went out dug the bike out and went for a ride after work.