Thanks for that link... finally "warm" enough to tackle (if only I kept my garage clear, sigh). While the images there were for a different car, it was very helpful.

Key difference was one-piece rubber windshield trim and one piece intake vent. The intake vent on my '93 300E is a one piece unit with 3 different vents... I thought from comments in other threads that they pop out (they don't). The center unit is hooked into the adjacent drains, with screws under the aforementioned rubber windshield trim holding them in place.

Once you get to the wiper linkage and motor, the fix is easy. The cause appeared to be a stripped out linkage, as well as the drive wheel for the motor. I chose to replace the motor with a used one with good teeth and all is well. I also lubed up the transmission assembly which seemed to improve the overall speed of the wiper system.