the logo is from "deutsche post", the german postal service. they are involved in several different motorsport sponsorships so i can't tell from the logo alone, what they are doing.
I have seen them with yellow Porsche 997's on the Nurburgring with the Deutsche Post logo's on them. So I think that will be it.
It almost looked like at first one of those movie trucks you see in Hollywood packed with TV studio equipment....
Ahh sorry, I did not make it clear. To me that is 100% 599. But, definately not 100% standard. So when I said possible 599 I ment its possibly a Hamman/GTO/XX 599