I test drove a BM with run flats and they were more harsh than non run flats.
However it is not just the run flat that is the issue.
Run flats tend to come on bigger alloys. Bigger alloys also make a ride more harsh.
I didn’t notice any difference in noise though.
My BM has non run flats and slightly smaller alloys = way comfier ride quality and only very slight compromise in turn in etc.
I do find it odd that people go for M Sport spec etc and then drive like pansy’s or do not realise that they are making the ride more harsh.