Well, the catalog for Liquimoly, the Synthoil people, is here:
http://www.liquimoly.de/web/lmhomeen.nsf/pages/index_produkte
I do not link to oil dealers, but if you look at their web site you can find a link to 3 US resellers.
If I recall, Synthoil 100 was a 15W50 product back in the early 90's running about $10/qt.
If you're missing that product, their current line-up appears to include two full syn 5W40s (one diesel and one not) and a full syn 10W60.
http://www.liquimoly.de/web/lmhomeen.nsf/pages/index_produkte
I do not link to oil dealers, but if you look at their web site you can find a link to 3 US resellers.
If I recall, Synthoil 100 was a 15W50 product back in the early 90's running about $10/qt.
If you're missing that product, their current line-up appears to include two full syn 5W40s (one diesel and one not) and a full syn 10W60.