I nearly always vote for private sale if you're seeking a high ROI, but this one's complicated by the lack of a market--by which I mean only that there simply aren't many used FiSTs for sale, and so data is sparse at best, and so everyone's flying blind, and a private sale could take longer than one might like. If I were buying a used FiST in excellent condition with 5K miles, options as listed, I'd pay no more than about $20K, and anything over $18K I'd be wondering about whether I should. And a big part of the process would be consideration of what mods it has, and what the mod history is. If I suspect the thing's been modded like mad and then returned to stock, I'm not going to give as much for it. That said, carefully kept records of all mods/maintenance goes a long way to feeling good on both ends. A sales manager at the local Ford dealer is definitely not going to give you top dollar, though, especially with so little clear data on value. A Subaru dealer will probably be even more reluctant to give you what you think you should get.
