If you don't mind sitting on them for a little while post an ad up on craigslist. Some guy with an 05-10 v6 might want to drop them in for a quick and cheaper dual exhaust setup.
I only suggest that because guys with 99-04 GT catbacks were throwing theirs away and then v6 guys started wanting them. People were selling takeoff catbacks for $150 when they were the hot item.
12 Black GT500 SVT PP l 2.6 Pulley/Idler l Airaid l o/r X l 305 NT555R's l Recaros l
04 Azure Blue Mach 1 / 03 Sonic Blue 3.8 / 14 Sterling Grey F150 FX4 402A 5.0 / 11 GT500 R.I.P.