I can only recommend Karl Schweikart. He runs a private shop specializing on Mercedes. He's a really nice guy and definitely knows what he is doing. He is from Germany and was trained over there at Mercedes and then came to the US and worked as a head mechanic at one of the Mercedes dealerships in the Area. He has probably been working on Mercedes for >40 years. He eventually opened his own shop and only works on Mercedes. However, most importantly, he is very fair and won't rip you off like most other mechanics will. Performance stuff is not is specialty, however he will do as good of a job (probably better) than any other performance shop in the area. He is the only person I trusted to do work on my supercharged C43. Give him a call, tell him Charlie sent you. What suspension setup are you considering?
Mercedes Haus Schweikart
(214) 744-0093
121 Leslie St
Dallas, TX 75207