Mrmjoet, you have to be more specific. What do you like to do and what would you like to see in particular. There's so many interesting places and things to see.
I can propose Romantic Road, German and Swiss Alps but I don't know what you like.
Mercedes and Porsche Museums are interesting and I recommend them. I did BMW Museum and Factory Tour in Munich, too. Avoid motorway between Stuttgart and Munich as there are extensive roadworks. Not sure when they're going to be finished.