On Fri, 26 Sep 2008 13:56:08 -0700 (PDT), "Robert M. Gary"
wrote:

The only thing I can tell is that they might
require you to use the Merc lubes while you are still under warranty.

-Robert

I believe that is illegal. I know that car manufacturers cannot
dismiss warantee claims if you didn't have them do all the recommended
service that is in the owners manual. All you have to do is regular
oil changes - and you can have them done anywhere you want (including
do it yourself) using any brand of oil you want. That's the law.