I was wondering the same thing. It was done by an artist, so it might have been done mostly on color and what the artist thought were the coolest looking cars.
We have 1 P1 class champion, 3 P2's with the class champion in the second row, 1 GT1... well duh, and the class champion GT2. Why three P2's? I can understand an Acura being on the front row seeing as an Acura won Sebring last year. But why the Dyson? Not that they don't deserve recognition.
How about the drivers...Looks like Marco Werner in the Audi, Chris Dyson in the Dyson Spyder, Must be Jamie Melo in the Risi Ferrari (red-ish helmet), Scott Sharp in the Hicroft Acura, and Timo Bernhard in the Penske Spyder (hard to tell but Timo is the only one with black on the top of his helmet).