Ah, yet another 'tyre debate'.
My 2p worth:
Unless you are a) a professional racing driver and b) drive on the roads like one then I would challenge anyone to notice any perceivable difference in ANY make of tyre.
Controversial I know but I have never, ever, thought "these tyres are not very good" about ANY make of tyre on any car I have owned or driven. I am not a racing driver, though, just an average car driver going from A to B.
Even runflats are OK, just not on the E89, as the suspension is too firm already and they just exacerbate the problem. I have runflats on a 440; they are absolutely fine as the suspension is a lot more forgiving (read better).
People on every car forum I've seen in recent times will always recommend the PS4S; for what reasons I am sceptical. They are fine, but so are many, many other makes IME.