Okay I've been sitting on my FCR from TT for over a month now.* The weather is starting to get better and I'm getting itchy to get it together.* Anyways my ? is I currently just have a WB slip-on and I want to upgrade to a full exhaust.* After ALOT of reading I'm still confused about jetting. ** I'm about 1200ft and the main jet is 160.* With a new exhaust cork out it should be fine.* The muzzy says 96db or under with silencer and spark arrestor, 97 or so with just spark arrestor, and over 100db with out both. Will I have to rejet everytime I put the spark arrestor*in or can I just put a 158 main jet and leave it?? I haven't heard a full muzzy yet and I might just leave the spark arrestor out if its beardable. Sorry for my confusion!! ps I have my mind made up on a muzzy. Cheers!