My position at this point is I will run whatever comes out of the pump for the following reasons:
- It just so happened my first fill up was at a station with crap diesel and the car got quite clattery because of it. I've since tried a few other stations and found the car to be considerably quieter leading me to believe they have better quality fuel. So, I'll stick to stations I know locally and roll the dice when traveling.
- The car is new and I while I wouldn't mind having a higher cetane rating and pump lube to keep the noise down and be more efficient a lot of these products also have chemicals that swell o-rings and extra detergents that I'm not sure are necessary or even good for the engine.
- It says right on the filler cap "No additives". So, I'm not going to put them in there and if shit goes south within the next 4 years BMW can deal with it. I'd rather not give them something to point the finger at. I'm not in it for the long haul anyway, I'll have a new one before the warranty expires.