looking for a gt500 axleback for my 12 5.0.. was going the roush AB but decided to settle with gt500 ..
Here they are on sale for $280 with free shipping: Ford Racing Mustang GT500 Axle-Back Exhaust Kit (11-14) GT M-5230-MGTCA1 - LatemodelRestoration.com
I ordered a pair. Depending on how they sound, my Roush AB will be for sale.