That 2006 Saleen for $46k seems pretty overpriced, although its also modified. A standard S281 S/C'd Saleen puts out 465 hp, and they claim 500 hp plus. The extreme puts out 600+, so we know its not that. The 2008 Saleen S281 RF (not exactly sure what it entails, but its supercharged) has an MSRP of $49,995 brand new.
Another perspective: on ebay, you can currently pick up a new Roush 427R for under $48k. There's another listed for $38k, but it seems like a scam. It says new with 12 miles, but it is being sold by a "city living student" instead of a dealer.