I am selling the flowmasters from my Shelby GT 500. They came with the car and I have replaced them. They should fit 05-09 GT's and GT 500. Here is the link on eBay
Mustang GT/GT 500 Shelby Flowmasters with tips - eBay (item 160577808717 end time Apr-30-11 12:14:19 PDT)
Mustang GT/GT 500 Shelby Flowmasters with tips - eBay (item 160577808717 end time Apr-30-11 12:14:19 PDT)