You should inspect your W210 Upper front spring perch for any rust. If you see flaking or really rough undercoating by your upper spring perch, chances you got rust. Also inspect the joint between the upper spring perch and the body. There should be mastic filler (chaulk)... that might be falling out... if so, you also got rust there.
Inspect your front springs on the bottom... on the lower control arm. Look for a crack within 5" of the end of the coil. If you got a crack, chances are you got broken springs.
Rear springs are not an issue.
I recently worked on my folk's 2001 E320. One front spring snapped while we were working on sway bar links and sprung out. Thankfully, it didn't kill my friend. I was working on it only a few minutes earlier. So we decided to change all the springs to Eibach Pro Kit.
The second front spring was already broken when we compressed the spring to remove it.
We also had complete rust through on driver side upper spring perch weld... only 50% of the weld was left but that's like 75% of strength is gone. Had MB repaired it for $800 for one side.
With new upper control arms, all 4 sway bar links, dealers replaced lower ball joint a while back and new Eibach Springs, the handling performance has increased tremendously. The car now steers like a go cart with almost same ride quality if not smoother. Very slightly firmer that is only apparent on harder bumps but not rough at all... I'd classify it more Euro handling rather than mushy ride of stock.
Understeers are all eliminated.