I bought my kfx400 used and came with a FMF Powercore4 can and mid. Would adding the Powerbomb header add much? Or should I wait until I go to a big bore kit? It has Hotcams and K&N no lid and jetted. I assume adding the new header would require re-jetting?

 

I have the PowerBomb Header and the Ti-4 Muffler (plus EHS airbox lid and ProFlow foam air filter). I put them on together, so I can't say what the difference with and without the header would be, but I really like the combination!