What should I say?
All I can say is if I read this thread and knew nothing about what was being said, I would be full of the wrong impressions.
Neil, had it right about the tech doing the alignment not a machine. But he has it wrong about how specs matter and what to do with them. if you want your car to drive right there IS NO spec to accomplish this. This is where the tech comes in. It is his responsibility to read the handling and the numbers and figure what to do. IFFFF he does this within someones factory specs.... great for him.
The actual readings will not change with your wheels. What changes is how your car reacts. The car NEEDS to be aligned with the tires that ones wishes to drive with. If the settings happen to work for driveablity with different tires , they should. BUT, tires make the car. The ones you are going to use are going to make the car ride like crap. They will have so much influence over the handling that the only hope for correction rests with an experienced MB/alignment tech. One whose shop is situated where he can do at least a 60mph road test before and after.
This goes for any alignment shop. If they are tight,in a city situation,that prevents proper road testing, they will not do the road test. One doesn't become good at aligning cars unless road tests before and after form the basis for your experience.
If I were chosing I would place the Alignment first in the term MB/Alignment tech. An experienced alignment tech will do better with whatever he aligns than a less experienced tech. Having ones experience be with MB finishes the deal, but given a choice between either factor I take the alignment experience to be more important than the MB experience.
Bosch Master, ASE Master, L1
33 years MB technician