I have Michealin Pilot Sport II's, and I highly recommend them. In addition, I have recently bought "BF GoodRich G-Force Sport". I think they are new.. not the KFS ones... just G-Force Sport. Anyhow... GREAT tire. Very quiet, made my Michelin and excellent grip. They are half the price of the Michelin PS IIs and in my opinion just as good. I dont drive my car very hard though. I just want good grip with a quiet ride. I use about 32psi in the front and 35 in the rear. If I have a full load of luggage and two passengers I'll use a little more.
Also, stay clear of Kumho etc and other Korean tires. You get what you pay for with tires. I had Kumho and one other name I can't remember and I will never go back. The road noise was horrid. Try the tires I mentioned and you'll love them.
You should get winter tires as I've yet to find all seasons that do summer and winter equally well. Depends on your winter. Where I live we get lots of snow and ice so winter tires are nearly required. Plus, you hit one curb and you will end up paying for more than two sets of tires anyhow...
With the DSC and winter tires the 3-series does a good job in the snow.