I've heard that the B230's alloys are more prone to corrosion (from wrong coolant) than earlier red blocks -- don't know if that's true, but there are a few notes on this forum about noticing corrosion as seen on the underside of the thermostat housing, for instance.

re: "...Like red stuff from the dealer?...."
I think you meant blue, right?

In any case, the best antifreeze for these cars happens to be basically the same as always specified for Mercedes as well as Volvo, a Glysantin type antifreeze: it's called a HOAT (for hybrid organic acid technology) that today serves for extended intervals, typically 5 years/100,000 miles. Like conventional Euro coolants, it's a low-silicate, no-phosphate formula designed to pass European hard water tests. The reference to OAT in HOAT is for an organic acid inhibitor called benzoate.

Zerex Extreme G-05 is one example, and Mercedes uses this, too.

Volvo uses Type C (blue) Glysantin, also designated G-48.