One more thing for instability in 'crosswinds' or roads with 'tire troughs'.
I have noticed on several higher mileage 124s that some benefit from a steering box adjustment to take up excess play in the box itself (before the steering linkages are manipulated at all).
Mine was particularly bad, needing several turns, but a friend's improved noticibly with about one turn on the adjuster.
Have an assistant manipulate the steering wheel within the play range, and see how much movement there is before the steering arm moves. This adjustment will also improve 'center' feel, but don't overdo it, or there will be binding coming off of center [no need to ask how I know this].
I have heard that the rubber 'steering coupling' is also a wear item, though I have not yet personally seen a car with visible play there.
At $50, I could not justify a pre-emptive replacement.
My understanding is that the steering dampener is really only useful for compensating for other worn steering components, and does not actually cure anything. May prevent some 'bump steer' feedback under different conditions. Shocks and springs are also not leading culprits for this flavor of instability.
As others have mentioned, the 124 is indeed rock-solid in the crosswinds when everything is in order. I would rate it well above average in this regard. It certainly took a lot of weekends under the car (and some dollars) to get there, however.
Best of luck.
1986 300E 5-Speed 240k mi.