This got me thinking, or wondering more likely, that scaremongering by certain parties who may benefit directly or even indirectly have their own agenda with such statements. I'm not an engineer and i can see that extremes, as is often the case in life let alone motor vehicles, is likely to be bad. However, i am also very aware that BMW and others do all that they can to protect their network of 'stealers', who lets be honest arent mechanics, they're fitters at best albeit very expensive ones at circa £200 an hour, with computers basically telling them simply what to replace, as opposed to attempting to repair. This is where specialists are usually great and better informed, they open stuff and have a look, not just unbolt, discard and replace. They learn like old school mechanics who fixed things becsuse they could and wanted/needed too!
Anyway, back on subject who, if anyone, has factual knowledge on whether non runflats are truly bad for the X drive aystem?