It's best to do either a jetkit or shim the needles (see the thread on shimming here: http://www.newninja.com/how-to/shimming-the-needles/ ) Shimming is basically a cheap way to jet.
It's not necessary, but it will help you get the most power out of your new exhaust. it'll help you get more power even without an exhaust.
Jester
It's not necessary, but it will help you get the most power out of your new exhaust. it'll help you get more power even without an exhaust.
Jester