It can be the design of the wheel hub on the Carrrera GT which is the same as the ring around the exhaust port except for color to the fact that Porsche has kept the style and shape since the 356.
My added feature, take a listen. http://www.youtube.com/watch?v=fdePhx9HVjo
The thing about this place is its casualness. John Dixon, the owner, uses the Porsche colors as themes and yet does whimsical things like the murals or the dropping of a VW through the roof. By the way, blow the pictures of the murals up and look at who is in them.