i have a 2000 400ex and i would like to have either a pro cicuit or white brothers slip on silencer i do alot of jumpin and racin againest faster machines with more mid and top end witch would be the best
also is the k&n power worth it

 

You need to check out last months issue of dirt wheels mag. They do a huge test on dyno and track, testing 10 of the most popular pipes. It is worth it, get it. It answers all !!!