From your video it looks as if the noise is coming from the front-right corner (passenger side). I'm not familiar with the W211 suspension, but it sounds like something rubbing. Any rubber bushings in there that could be lubed with silicone spray? Don't discount the shock absorber...

With a noise like that, you should be able to replicate it by pushing firmly on the corner you suspect the noise to be at.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]