I read about your interest in going to the factories. I was just at both the Porsche and Mercedes factories, and both of their museums in Stuttgart. The Porsche factory tour was incredible, you are just about 5 feet from the guys building the engines, great tour. The Mercedes tour was also good, seeing the huge stamping facility was good. The Porsche museum (right next to the factory) is small for not great, but it is only 20 feet away. The Mercedes Museum was very good, went there twice....doug