So, I changed my own oil for the second time a couple weekends ago on my 07 335i (97K miles). I'm an oil-change convert now but that's another post maybe.
This past oil change was the first one in my car that was done with a Non-OEM (but still BMW approved) oil and filter. The oil I chose was Mobil 1 0W40 Advanced Synthetic and I got a Mann filter. From what I've heard the Mann filter is the same as the filter supplied by the dealer, all I know is it was OEM-spec.
Now, this may all boil down to the placebo effect but since I've changed my oil with the Mobil 1 0W40 for the first time I have noticed significant smoothness at idle and better performance vs. the standard BMW oil, which, from my research is a Castrol-produced 5W30 synthetic.
So I guess my question comes down to this: Has anyone else switched from manufacturer-supplied oil/filters to OEM-spec alternatives and noticed better performance with that change?