... & before. "Newer" w/b 140 Series & on...
You know: back in the OLD days when anti-freeze was just that: anti-freeze.
The cracked plastic radiator at the upper tube is, has, and will remain a manufacturing/design weakness (note: I didn't say "defect") on the SVX. Actually, there were other issues re: the radiator that were much more serious that had to do with the tranny cooler section, especially on the initial (1992) models. The cracking had more to do with vibration vs. corrosion. A radiator replacement at 12 years & 125K is not going to send me into paroxysmal depression.
I also seriously doubt the Subaru suppliers used the same plastic as MB. Maybe, but unlikely.
That Mercedes once used oil that was not SG or SM (or 502.11(3)a(2)iii) rated, or even SYNTHETIC, and transmission fluid that was not equal to Dexron III/Mercon, etc. does not mean that using BETTER more sophisticated fluid products in "older" (there's that word, again!) MB's is not a good idea.
Cheers!
p.s. My 450SE has a METAL expansion tank and the original radiator.