The dim odometer is just a bulb replacement job in the cluster, very easy on a w210.

What about blotchy LCD ? The LCD of the odometer looks as if it’s deteriorating

That requires a repair of the cluster.

At 221,000 miles I'll be doing the conductor plate in my 98 E300 this week. Does not look like it needs any kind of programming based on what I have read so far.

Plug and play...….

Its literally plug n play if you had no errors.

No errors, just hard shift between a couple of them, not wanting to upshift sometimes and slow to go into reverse. I "time" myself in the shop by listening to Car Talk podcast. I went thru 2-1/2 shows while doing job yesterday. Everything back to norm today.