Actually this is the Universal Studios Ecto-1 replica. It started its like in USF Orlando as the show car for the Ghostbusters attraction, at the time it was a highly inaccurate replica. While all the elements where there, the roof rack was way off, and the door decals too small. After the closure of the attraction the car was held is storage until sold off to a private collector (name withheld). This collector then restored the car and gave it a much more accurate roof rack, but decided to leave some inaccuracies (like the strobe light bars instead of rotating Code units.) It was then sold at a mere 30 something thousand dollars (to be on display in a museum) apparently it never went there as it ended up being auctioned.
The Ecto-1 restored for promoting the video game is the REAL Ecto-1 used in Ghostbusters and at the beginning of Ghostbusters II. That car HAS NOT left the ownership of Sony, and I doubt it will. If it did, I wouldn't be surprised if it ended up in Dan Aykroyd's hands.