I currently own a 08 6.4 with a 5" magnaflow exaust straight piped. ive had 2 I the past with a 5" diamond eye turbo back straight pipe. I bought this truck with the exhaust already on it. As of right now, it has no noticeable problems at all, turbos spool fine, it is just quite. I thought it was just me at first, but then my friend came over with his 6.4 to compare the two and his is 5x louder with the exact same mods (5" straight pipe, cold air intake). What could this be? should I just replace the exhaust?