Porsche Cayenne Roadrunner
From a www.carpassion.com member. Translation:
"This Cayenne Turbo was optimised by the internal education department of the Leipzig Porsche factory. It has 4 seat shells (like a racing car), a roll-over bar and is lighter than the normal car. The sound of the V8 is a pleasure for every fan. The car is used as "taxi" for demo laps at the Porsche test course there. Basically this would be the Porsche-equivalent of the BMW Ringtaxi."