When the autobahn is in your backyard, you're going to build some pretty insane cars to drive on it. There are lots of German automakers who build very fast cars, but Porsche and its tuner friends have taken nearly half the spots on this list.
The 911 GT3 RTS 4.0 is a factory-prepped car, and the Porsche guys really poured all they had into it. Thanks to their passion (or insanity; it is so hard to tell the difference sometimes), the Road & Track testers were able to push this car to a hair over 200 miles per hour. If you watch the video, you can hear the exhilaration of the guys in the cockpit when the speedo hits 323 kilometers per hour and the driver starts to back off the throttle. Also note that this run was done at night, when traffic was a bit lighter.