Apologies, typo on the original post, a 520d would, of course be a B47, not B48.
Fair point on the N53 weaknesses. The last 5 years with the existing 530i has me mentally prepared for the possibility. Hopefully not tempting fate by saying that I've had no injector or HPFP issues thus far. 530d/535d's are very tempting but pre-EU6 NOx levy costs would rule one out and a 2016 example is probably a greater than 30% uplift on a same age 520d price and nearly 50% on TCO, so would probably impact the "fiscal space" of the weekend car, although TCO over 3 years would still be less than the older options.