I have not had any luck with alignments anywhere but at the dealership. In order for a Mercedes to be aligned properly, all the suspension components have to be in decent shape to start with as others have mentioned. But one must also lock the steering box with a special tool(bolt) and insert a tensioner rod between the front tires to take up any bit of slack in the suspension. Ask the techs if they use those tools. If not, they aren't doing it right. When I ask those questions, I get one of two responses, either the "deer in the headlights" look of "oh, our machine takes that into consideration" which is pure BS.

Len