Odd suspension (?) problem -- W124
I'm having some suspension issues (or at least I assume it's the suspension) with my 1993 300E with 115,000 miles. Basically, it's not happy at high speeds. Keeping it in a straight line takes entirely too much effort, and it just feels loose. Also, periodically there's a slight shimmy/vibration at the steering wheel. The car also sometimes rides very roughly over freeway expansion joints (my Miata with Konis and low-profile tires rides better over them).
In the past six months, the car has new Bilstein shocks, a new steering dampener, and new thrust arms. I was hoping these would solve the problem, but no luck.
I know I'm due for a new belt tensioner shock, and the tires need to be replaced this summer. Don't know if either of those would affect anything, but thought I'd throw that out.
Any ideas what my next step is? I appreciate your help.