cvcphoto, Studio13 in Leinfelden Echterdingen (just south of Stuttgart near the airport) is a first-rate lab.
If you speak german you might want to ask your question in one of the german forae. There are quite a few people from the Stuttgart area.
http://www.schwarzweiss-magazin.de/
http://www.aphog.de/forum/index.php
http://www.vfdkv-forum.de/