It's a scam that's been going around for a while. The seller is new and has zero feedback. He'll send you a link to a bogus escrow site and clean your credit card out. Cancel the transaction quick! Also, I live very close to Dumfries, tell him you have a forum buddy that you want to have check the car out for you. That should shut him down!
Update: just checked the report on this car and it's registered in Loudoun County, which is were I live. Dumfries is in Prince William County, about 15 miles south. Also, the phone number posted leads to a management company in Leesburg, VA which is in Loudoun County.
http://www.emiroglumanagement.com/
I'll be glad to meet him at the management company and check it out for you.