One of the first things I did upon buying my 335i was to check amongst other things the wheels as through various forums I'd made a note of the fact that the 230's on the SE spec model were prone to cracking. Was pleased with the inspection on the ramp and found nothing whatsoever to worry about and the wheels were perfectly round no flat spots whatsoever.
I'd never run a car on run-flats and stomached the Bridgestone for around 2 weeks before changing them for Non RFL's choosing another set of Continental Contact for my chosen replacement rubber. Ride is a lot better and its a bit better on the road in terms of noise which is a bonus.
The wheels though are an issue but to a degree there's enough evidence out there to back up the claim that the Bridgstone and dare I say other run flats don't help their cause in terms of longevity