My DS is loud at 103 db. I have the FMF power core 4. If I put on in the quieter end cap what should I expect? Less power all around? I asume I need to reduce my jetting? I also run an open airbox with no snorkles.. Will I need to adjust that?

 

I'd say get a real pipe... The core will only make an already bad pipe worse...

 

Dunno but rumor I heard at the Sands Sports supershow is that CA is going to make the limit even lower then the current 96 db soon.