Two decades of owning/driving BMWs - I've only ever had the oil changed at the dealership using BMW's recommended/supplied oil. Zero problems. For a road car, I wouldn't overthink it. BMW's oil is, most importantly, fully synthetic and rated for the 15k mile service intervals. The aforementioned alternatives rated for "long life" and fully synthetic (Mobil 1, etc.) will be just fine, too.
My BMWs have always been 100% dealer maintained, and therefore the cars got what the dealer used - zero issues with engines (certainly none related to oil quality). With the N63 line of engines, something completely unrelated to oil is likely to get you first.
