Police cars that are not unmarked are actually quite beastly. They are all tuned up to make sure to be able to keep up with some of the extremely fast cars that frequen the Autobahn. Basically you’re going to get caught no matter what kind of car you’re in. However, police chases like you see on TV do not happen on the Autobahn as German law doesn’t allow the polcie to put innocent people in danger. So, technically, people can and do outrun the police.