Project Repo Racer, our 2011 Mustang Shelby GT500 is getting an exhaust upgrade! It turns out that it already had a MBRP exhaust on it, but I had already ordered another MBRP exhaust. The new MBRP exhaust is louder and has basically no mufflers. Installation is pretty simple and took about an hour. The original MBRP exhaust was the street version and the new one is the race version.