I went to my local auto-parts store this evening and was surprised to not find the Zerex G-05 stuff that's safe for MB cars. The counter guy told me the new Prestone stuff is supposed to be usable in all makes and models of cars, including ours. I didn't buy any but read the bottle on the way out and, sure enough, that's the claim.
Go to
http://www.prestone.com/ , click the news link on the left, and click the 'Prestone® Launches Universal Antifreeze for All Makes, Models, Colors' link. I'd link directly but, well, the site is braindead and doesn't allow it.
Anyone tried it yet?