That's one reason why i'm missing the days of having some really exotic sounding inline 6's, the E46 line was a good example of this.4 Series
I've been driving my 428xi G.C. for nearly a year without a hint of a problem. We really enjoy the car. The little N20 4 cylinder turbo motor is slightly less refined and smooth than the preceding 6 cylinder motor but the performance is pretty remarkable. On cold start it sounds a little like a small John Deere diesel tractor but quiets down pretty well when warm. We're currently driving our third car with the N20 turbo and we haven't experienced any problems with them after more than 100K miles driven. And, we haven't found the engine noise particularly objectionable.
There were several TSBs on the 2014s, mostly for airbags and headlights. Not much since then.
Go for it.