So I returned my exhaust back to stock to get some warranty work done. My normal exhaust is a 3" JBA offroad x-pipe with 3" dynomax bullet mufflers turned down at the axle(very loud). I wasn't sure if I noticed any gains from the exhaust alone because I did a cai and Bama race tune at the same time. With my normal set-up I can steadily pull away from my buddy's 2014 Mustang with similar mods, but only GT500 mufflers for the exhaust. We have gone from a roll so there is no driver error involved. Once I went back to stock exhaust we decided to give it a go, he beat me like he caught me stealing his chickens.

 

Wider exhaust will free up some power. Not to much but it will help a little bit

 

More than a little bit, gonna have to trust me.