The F28 needs a no-bull fully synthetic.
Just changed Mobilube for Valvoline synth...bollox
When I got the car it had Vaux synth, and Mobilube made a noticable difference. I put it down to the age of the previous oil.
Well, 2 years later the Mobil stuff was near-new, and the replacement stuff feels inferior (you can tell immediately by the gearchages)
Moral of the story: Mobilube is getting pretty hard to find nowadays, but you're worth it.