I used to have Bridgestone runflats on my E90. They were ok in the beginning but got much louder and wore out very quickly, by 22k km my rears were almost flat. Switched to Michelin non-RFT and am very happy but even then the PS2 can only last 40-45k km only.

The F30 without M-sport today isn't so bad, I was very impressed with the grip although the wider 255 M-Sport rims should be better though.