Your best source of limited-slip differentials (LSD) is RC-Imports in Rockville, MD.

Give Rick a call. His website:
http://www.rc-imports.com

You may also try BergWorks (http://www.bergworks.com), but I don't think they are open for business yet.

Tell any of them Neil in Santa Barbara with the C36 wagon sent you.

:-) neil
1988 360TE AMG
1993 500E