Dwight:
M-B offered a warranty upgrade to pre-94 500E's that were experiencing excessive brake fade. The upgrade was to fit 600SL front brakes, as were incorporated on the 94 E500. I'm sure you're aware that others have retro-fitted this upgrade with success after searching the archives.
You can find out whether you have the aluminum (pre-94) or iron brake calipers with a magnet
Michael Curcio dropped me a note on another thread to advise that his experience with cryo-treated front discs was not good and he has reverted to stock discs and upgraded pads.
Good luck!