I am about to order exhaust Monday and am leaning towards this system due to its' quiet reputation and claimed power gains. I ride near housing areas and have had no complaints with stock exhaust noise levels. Thanks

 

I have rode a 400ex with the complete big gun system on it and I was none too impressed it. In a drag race it is dead ever with my stock 400ex. As for the quite reputation, its way to loud to be riding near houses and its louder than the white brothers e-series. I have ordered the new fmf power core four squared silencer for mine it
should be here the end of this month

 

ss396, from whom did you buy your new FMF system? How much? What kind of jetting changes did they say? What kind of sound levels did they report? FMF told me that it's quieter than stock by 3 decibles. I'm excited to see if they are for real.

 

I had the same question a week ago. I went with the white brothers s-bend and it's incredible on low to mid end. I am pleased with it and it was only 225.00. I saw a lot of fmfs and was not impressed with them this weekend in the dunes.

 

I ordered mine from rocky mountain atv , I got the s\a version and it was $242.99. When I talked to FMF they wouldn't give me a exact decibel level, but said that on most bikes it was the same as stock or lower. As for jetting they said that you will need to go 2 sizes larger on the main jet with a stock filter. With a K&N or Uni, you will need togo 1 size up on the pilot jet also. With no air box lid they said to go one more on the main.