Here is a link to a Ebay Auction listing for a 08 V6 stock exhaust.
eBay Motors: 2008 FORD MUSTANG V6 STOCK EXHAUST OEM (item 300220170146 end time May-04-08 17:10:21 PDT)
What I am referring to are the red/brown colored pieces of round rubber on two brackets. One welded to the y pipe, the other welded to the back part of the muffler itself.