Our Mach 1 is going for startup next week, but has to hit the exhaust shop first. I'm debating between 2.5" and 3". I am also looking at Borla ProXS or XR1s for a more unique sound. Pipes will be rear-exit. I have a set of 2.5 Magnaflows and they just weren't all that awe-inspiring. I've put 800hp through 2x 2.5 before, so this is less about performance and more about sound. We're guessing the Mach 1 will be around 700-750hp max when all is said and done, street use only. A few exhaust guys have said you can get 3" under a '69 Mustang but it is tight at the rear axle.
Has anyone run dual 3" on an FE? Was it obnoxiously loud? My wife runs Borla ATAKs (5.0 Coyote), and I ran ATAKs on a '14 GT500, so that's about where I would like to be noise-level for the street. We're not obnoxious drivers either.
Looking for feedback before we start welding things up