You mention the suspension components were replaced, does that include the bushings?
You might also want to try the tire pressure test specifically to the front and then to the rear to isolate the problem.
I second the suggestion to find a professional independent alignment shop with the latest equipment to check alignment. The MB shops in my area don't have the latest and greatest equipment and can only do so much when it comes to aligment and wheel balancing. Ask for before and after alignment figures, most good shops will print them out. If you post the numbers I can compare them to mine and let you know if anything is off.
02 C32 AMG
84 190E 2.3 5 Spd