Had the PS4 's fitted y'day; I'm reserving judgement until I've covered a few miles as came from 888's, the sealant thing they come with, and the fitter told me he'd put 2.5bar (33psi) all round; said he does this with every car!
I mentioned all cars have different recommended pressures, his reply was I'd get better mileage on the tyres.
So the pressures; fronts were 39 & 34, rears were 36 and 34; may be I don't trust that garage so much now!
(I've gone with 33 fronts and 31 rears for now)
They only come with 7mm. Pretty sure the last set of PSS I had fitted, just over a year ago, had 8mm.
Seams this is now the norm
http://www.tyrereviews.co.uk/Tyre/Michelin/Pilot-Sport-4.htm (first review re tread)
(includes a good summary of tests won and some mixed reviews, includes a couple of beemer drivers who much preferred PSS after fitting PS4... must not wish I'd bought PSS...cheaper, more tread, massive reputation for being brilliant incl my own experience...but PS4 won all the tests and loads of good feedback on here, better all round performer and my main use is as a daily...ommm)