Six months ago I left a review for "MBI Motors", Portland, OR. A year ago I bought a 1995 E 320 sedan, still in good condition, and have been "making it perfect".
I have now had 6 Excellent experiences with MBI: differential mounts, full front brake parts, water pump, serious oil leak, routine tune-up, alignment. Each time, beforehand, I talked with "Corbin" (newer owner) about what needed to be done, and the cost. Each time, all went Flawlessly, and at estimated cost.
This is a -remarkable- shop. And these are very good people to work with. They have a comprehensive website named "MBImotors", which gives some details of their history & experience in the "About" section. All the technicians that I have talked with were in the 20-to-30 year range of experience, and Very Sharp. (old owner, "Sig", still spends every Monday there)
What seems to make this medium-sized shop work so well is: Corbin has 30 years of solid Mercedes experience, and actually checks out the problems on the cars when they come in, and then assigns them to "just the right technician". He also kind-of "inspects the car" while the work is in progress. He has given me good-clear answers to all on my technical questions, so I know "exactly what is going on".
You can simply go by the shop, and talk with Corbin, or others, and you will get a good idea of the quality & reasonable cost of their work (which is how I found the place...). Good Thing ! Ed in Central Portland.