most of the issues with runflats have been ironed out in the current generation of tires, with ride harshness being the top of the issue list.
impact damage (pothole induced sidewall ruptures aka bubbles) should be lessened now that bmw has increased tire diameter from 25 to 26-- an F30 running on 18s has the sidewall height of an E90 running on 17s.
Past: 2001 Orientblue E46 330i
Past: 2004 S60R 6MT
Past: 2007 E90 335i 6MT
Past: 2010 335xi ZMP, BMW Performance Kit, BMW Performance Exhaust
Present: 2013 335i 6MT ZMM/ZDH/ZTP/3AG/494/508