I went to 215 on the f56 jcw with no issues.You need to watch for rubbing if you go up a size. It’s only 205s on the Cooper S and JCW Mini’s, if you go up to 215 or 225s you can get tyre rubbing depending on the brand.
The stock P7 cint.... We're terribad.
Michelin PS4 have been excellent for 3 years now. Due a change very soon.