My only experience runflats is on my stepsons Mini Cooper S. When he replaced them with regular tyres, the tiringly harsh ride became almost civilised..
Out of interest Wigwam, did your previous X1 have run-flats? Our X1 doesn’t, unfortunately. Like Elliot, I have had numerous cars with them (3 and 5 series) and the ride was sublime in all of them. No harshness, noise or ride quality issues whatsoever.