Have a brand new in box set of Roush 2011+ Mustang GT Extreme Exhaust Kit P/N 421127 also fits 2011+ V6. Upon examination, box was dropped and made a flat spot on one connecting end, see bottom edge of pic. Won't bother install but want to disclose it. I got these when I ordered the supercharger but don't care for the sound from sound clips I've heard. Prefer touring mufflers (ford racing/borla). List is close to $500 but I'm open to offers! I repackaged the box with foam to prevent any other damage.