There's a bunch of things you need to do to make the steering factory new and this applies to almost any Mercedes
1) There's an adjustment on the steering box. Ideally you remove the box and adjust it to spec on a bench. In practice you tighten it up, to the point there is some, but minimal free play.
2) Replace the idler arm bushing and steering shock.
3) There may or may not be a flexi disc and u joint in the steering column in the engine compartment. Replace them.
4) There are two or three bushings in the steering column itself. Remove it and replace them.
Do this is it will literally be as good as new.
Number 4 usually makes the biggest difference. And yes, it's quite a difference.