One issue that rarely seems to come up in these threads is that if you rely on a breakdown service in the event of a puncture, you really need to check the smallprint if you decide to abandon runflats. I have a policy that covers me throughout Europe but only if OE or direct equivalent is fitted.
So I'm fine without a spare - as none was supplied - but if I ditch the runflats & go for a tyreweld & inflator combo, I may be out of luck if I need to call for help. Perhaps they'll still come out but just bill me afterwards. Perhaps not?
I found that the majority of of the pan-European insurance backed policies had similar clauses. I've been unlucky enough to have a few punctures in awkward locations over the years in my previous Z3 and also in a 330D Sport that was a bit of a nightmare with (expensive) tyres so for me at least it isn't a trivial issue. One reason I'm looking at this thread with interest is that a 'good' runflat might be a useful compromise.
Meanwhile I'm still on the Bridgestones and the famous 'glass' 326M alloys so for sure I'd like to find a way through this one. :?