All new BMW's are sold with runflats! So when 80% of the owners change them for non run flats your saying they are running around with invalid insurance? I can see this as it cannot affect the car in any way possible. It just you can supposidly get home without having to change for the spare. (which come on its good on BMW's as the owners dont want to have to change a tyre) .

Width yeah maybe.... But type of tyres from run flats to non run flats i cannot see it.