Up for sale are a set of Mustang GT Axle Back Off-Road Mufflers (2005-2009). I bought these directly from Roush and they were on my car for less than a week (roughly 50 miles). I traded my 07 GT in for a newer Mustang. These things sound incredible. Brand new they are $599.00 (see the link below).
Mustang Axle Back Exhaust GT, Off-Road (2005-2009)
My price is $450. I live in Lakeland, Fl, which is in between Tampa and Orlando, so if you're local we could meet somewhere convenient for both of us.