I think there a two factors potentially affecting the stopping distances:
BMW seems to have switched to low-dust pads, likely reducing performance. I'll just stick with the BMW pads as long as maintenance is free.
I haven't seen any reviews of the M Sport package meaning all of these test vehicles have LRR all-season run-flats. I don't expect the Goodyears EfficientGrips to be much better but the Pirelli summers should be. I'd expect the newer Bridgestone Potenza S001s to perform better and the non-RFT Michelin PSS to be even better.
I glanced at the F30 board and they have had the same discussions.