Where does one begin in replying to the posts of the past week? The attitudes of some of these posts can easily be perceived to be rather juvenile in nature, with leanings towards hostility, patronization, and lastly and largely assumption. I would have expected a greater interest in the sharing of knowledge with an open mind. Or at the minimum, the willingness to hear a differing point of view that is based on experience without the automatic dismissal of that perspective.
Furthermore, it is curious to see posts getting edited, in which the edits amount to a great change in tone and information. All the while, these edits are made without explanation to the community at large. Why is that? What changed in those perceived "truths?"
In the end folks will believe what they want to. For those that are on the fence with regards to this issue, I invite you to perform your own empirical testing, be it on the car or in the lab.
In my 20+ years, more than half of that as a respected professional and NOT a shadetree, the other ten working as an apprentice to various MB and Bosch factory and dealer trained technicians, I have seen enough evidence to convince me that OEMs are often quite different than OE in quality. I could reference my relevant mechanical engineering studies in manufacturing, QC, materials science, and other related coursework that provides me with the knowledge to substantiate my claims on a technical level, but the truth of the matter is that my findings in the real world of day to day working on these cars speaks louder. I have performed studies on my own cars as well as on those of clients' whom are Genuine parts only vs. mostly OEM. Most of the OEM users find greater frequency in the rate of their OEM parts failing as well as a poorer performing (as a whole, not only in 0-60 times) automobile as a result.
The whole is only as good as the sum of its parts. Some folks are into these cars for only the enjoyment of aesthetics and pride of ownership. Others are out for the experience to be garnered from an example that functions as the engineers who designed them originally intended. As I said in a earlier post, everyone's priorities are different.
Hearing directly from MB, the true "horse's mouth" in this matter, that OEM standards are often lesser than those of the OE adds further credence to my findings.
In the end, do your own research. Relying on information posted to an internet forum has no guarantee of being the whole truth regardless of who is posting it. Without your own personal verification, it is only hearsay.