I put the potenza s04s on my e90 with 17 inch sport package wheels in stock sizes. I have been very happy with the grip. It's a huge upgrade over the RE050a RFTs I took off. They are reasonably quiet so far - I have about 5000 miles on them. They are much more compliant over rough roads than the RFT were, but are stiff enough to still corner well.
The only gripe I have is that I had to send back a couple of the tires in the front 225/45R17 size because we could not get them to balance correctly and not vibrate. So I am not sure if at the time I bought mine they had a problem with manufacturing in that size or what. I have since sorted the issue and am riding smooth, but it was rather annoying to sort out. The 255/40R17 rears had no issues and balanced out perfectly the first try.
I do notice some slight flat spotting when the car sits for a a few days (ie parked at the airport). I upped my pressure to +3 over stock and it's helped (also helped handing feel). Not a big deal really, it works itself out after a mile or so, but confusing and annoying at first. If you drive your car every day it's not likely to be an issue. My car often sits for a while...