This is the latest scam out there. A bogus company will assume the identity of a smaller, well-established independent dealer and "highjack" it. I saw the same ad you did and became suspicious. I did some digging, and found out that there is a United Car Sales at the address that United Auto Sales uses, and yes, they have a B- BBB rating. However, the online company is a fraud. The website united-auto-sales was established on 7/27/10 (Unusual for a company with a 15 year history). A search of Google maps using street view shows a dealership there, but clearly NOT the type that would be handling the type of late-model cars the website.
I contacted the actual dealership owner. He EMPHATICALLY stated that they do not deal in repo cars. He had only recently heard of the "other" site, when he got a call from a man in Alabama wanting to know where his car was. The owner had no idea what the man was talking about.
I went to the website, and sent them an e-mail stating that I wanted to come by and purchase a car in person. No response. I also took VIN numbers from several of the cars they listed on the site and ran them through my AutoCheck account. Out of 10 cars, all 10 showed vehicle histories that were inconsistent with being available for sale in NC. Also, they all contradicted the "CarFax" reports that this "dealer" put on the site.
I found out today that the FBI North Carolina office is investigating this matter. I hope this helps you out. Do not become a victim!!