I just rebuilt my C class front suspension, and tie rod ends and ball joints can go bad. the rubber can tear on both.

How many miles on your car and what brand tires? If you have Conti's where are they made - written on sidewall.

What degree of vibration in the steering wheel, can it cause numbness in your hands?

to check spindle tightness and bearing you really need to pull wheel and remove brake caliper and caliper mounting bracket.

these cars front suspension are actually easy to work on,

Control arm bushings are a common repair on these cars - are these Mercedes specialist looking at your car. And when was the last alignment?

If tire inflation is good and you have shoulder wear on both sets of passenger tires, there is a likely camber issue.