My car is different from yours (1994 E320, W124) but I recently had similar problems at about 110,000 miles. I had an occasional misfire while idling. The car accelerated okay when gentle, but stumbled if I stepped on the pedal hard. Ran smoothly once at speed.

My local parts store didn't have Bosch plugs on hand, so I replaced the plugs (correct gap and torq) with Autolite plugs and that seemed to clear up the problem for about 2-3 months; then it reoccured. I then read in the DIY forum to how important the correct plug for my year/engine was, so I ordered MB-OEM plugs (I think F8 DC4 but don't hold me to that) and saw no improvement. Sigh. I noted this time one of my plug wire caps was rather worn and corroded. So I ordered a new plug set (about $100 I think) and everything has been hunky-dory ever since; I've had no need to replace coils. From what I've learned, these cars need a major tune at 100M+ miles so even though your plugs are new and wires may seem fair, it seems you're likely due for new wires -- especially if they are original. It was a fairly easy job and only took an hour or so. If the problem persists after new plugs and new plug wires are installed, then the coils would be the next logical step.