Tim, you hit the nail on the head. I can't tell you how much money I've spent on my cooling system thinking there were problems. I did, however, have a bad fan clutch (after the engine was hot I could grab the fan at the 12:00 o'clock position and move it about and inch forward and aft. Definitely bad fan clutch!! But to get used to an engine running around 212'F is still more than I can handle. I recently installed a 82'C Thermostat and now it never goes above 90'C (it is fairly cool out too so I don't know about this summer) so at least I feel better. But I can gaurantee most people out there are chasing a ghost problem that really isn't a problem at all.
Having said that, I found a radiator shop that is going to build me a custom radiator (thicker and wider) for $350.00. Why you ask would I do such a thing, because I too am obsessed with keeping the engine as cool as possible (around 80 to 90) at ALL times, not just in the winter like what we're in right now......I sure wish Mercedes had just installed a temp. sensor with a null area in it like most all other manufacturers, then no one would really know how hot the engine is running until the aux. fans kick on.
Okay, I'm insane.........maybe I should just unhook the damn temp. gauge and forget about the whole thing...Just kidding....