In order to put real cars in video games, game studios need to buy licenses from automobile manufacturers. Remember that Cayman shooting brake/breadvan mule recently spotted on the streets of Europe and supposed by many commenters to be a fake? It's been captured in Forza Motorsport 3.
Porsche Cayman Test Mule
Camera phones are turning into quite an asset in this business, as readers of various automotive news sites across the interwebs and around the world have turned into legions of spy photographers. In this instance, one such reader-turned-paparazzo (apparently in Italy, no less) caught on video what appears to be some sort of Porsche Cayman Shooting Brake test mule.