I was able to get the correct fan clutch from my local MB independent shop at a decent price and it fit perfectly. I cannot believe how much air the thing moves now. I did some long highway drives, each ending with some deliberate stop-n-go driving, and the temp gauge would only go slightly above normal....and then go back down when the car was moving at speed again.
I think I have this part of my stalling-while-hot problem fixed.
The downside, if you could call it one, is the noise.
The fan now moves so much air that the car sounds like my grandmother's old Hoover vacuum cleaner when accelerating.
No kidding. While the sound is reassuring in that I know the radiator and motor are now getting more air, it actually drowns out any exhaust note. So...there is only one viable solution:
MAGNAFLOW! Time to start the exhaust rehab project: Magnaflow cat, delete the stock resonator, new Magnaflow muffler and stainless piping in between.
I can't show my face at the next autocross with the car sounding like a turbine, now can I???