U can get a catback system or axlebacks! As far as full exhaust with header or mid pipe I don't think any would pass! U can get a mid pipe & then switch it out with the stock whenever u have testing!! Or jut find a shop that'll pass u there's plenty of those in the hoods! Haha.
-2012 Mustang 5.0- Stock (for now)
-2013 Mustang 3.7 (SOLD)- Best 1/8: 9.057 @ 80.67mph