Run-flats are a scam, you are
Run-flats are a scam, you are complete fools for believing the hype. Stop for a moment and realize most cars do not have run-flats on them, how many of those do you see on the side of the road with flat tires? Not many. Run flats are a solution for a problem that doesn't exist, in fact they cause more issues than they solve. Allow a run-flat to run under inflated just a bit and because it's reinforced sidewalls don't expand to support the weight of the tire they generate far more internal heat. The generated heat damages the integrity of the fabric that hold the tire together so when it's properly inflated, it fails. A regular tire doesn't do this, run it underinflated and it just expands it's footprint to support the weight of the vehicle, no is done unless the tire completely un-inflates. So while a run-flat handles full deflation better than a conventional tire, they actually are more likely to "run-flat" than a regular tire and given the same absent minded care given a conventional tire (ie we always forget to air up our tires when cold temperatures arrive in the winter) the run-flat is more likely to pull money out of your pocket - which I am sure BMW knows well.