Man, are you getting kickbacks from your local MB dealer or what?
You sound like a TV commercial! hahaha....
Seriously, I understand the warranty and updgraded parts portion of your statement, but otherwise, I see no reason whatsoever to pay dealer prices for the EXACT SAME part I can get elsewhere for far less. OEM is OEM, whether it comes from an independent seller or from an MB dealer. I know several independent guys who keep up with all the latest MB-issued upgrades and changes just as well as the dealerships...often BETTER on the older models, cars which most dealers have very little interest in.
There are independent shops around with techs who are just as good, better in some cases, than an MB-employed tech...some of them used to BE MB-employees! You don't have to pay dealer prices to get a good rebuild, but, of course, you do have to be selective about where you go.
My 2 cents...