http://www.flugplatz-konstanz.de/
if you hadn't found it already
I had a few problems with oil but just because I use 15W50 which wasn't always available. There was plenty of other oil available.
One other thing - when I was there a couple of weeks back, there was a fair bit of temporarily reserved airspace north of the German border and south of Munich which was being used in a military exercise. It wasn't marked on maps but it was notamed and there was a notam publication which had a graphical description of the area. Probably finished now but worth checking.