Man, are you guys late to the party. This came out at NAIAS back in January.
That concept has been around for a few years...probably before the 300 came out but not sure.
No, the Interceptor came out in January. You're thinking of the Ford 427 concept, which did come out before the 300.
If you'll go look around
AutoWeek's Web site, there's a video wherein Dutch Mandel interviews J Mays next to the Interceptor on the stand at NAIAS. The payoff is ~5 minutes into the interview when they fire that mother up. Let's just say that the cameraman wasn't quite ready for the guy in the driver's seat to put his foot in the bowl.
FWIW, the Interceptor is powered by a 5.0 Cammer which may or may not be turbo charged (press materials report 400hp; in the above interview, Mays says it has 500hp, and that sure sounds like a turbo spinning down). Also, the press materials say it has a live axle, but someone got down and looked at the IRS under the rear end.
Here's the video:
http://www.autoweek.com/apps/pbcs.dll/article?AID=/20070110/VIDEO/301100002/
The best automotive quote of the year come from an exchange between Dutch and Mays in that interview. Mays has just compared the Five Hundred to a Brooks Brothers suit (while the 300 would be a Versace).
Dutch: Is this a Hugo Boss suit?
Mays: I don't know if it's a Hugo Boss suit, but it's a big, bad-ass sedan.