Anyone been having loud road noise with the Bridgestone Potenzas?

My 2006 650i has the Sport Package, 2200 miles, and I have recently (in the last 200-300 miles) started to notice what sounds similar to "wind" noise, starting at about 25-30mph and progressively getting louder as the speed increases. It certainly could be the outside wind blowing around the car, but I haven't really noticed it much in the past and think it's coming from the tires.

I took the car to the Dealer and the tires were all out of balance - came that way off the truck. "The Dealers don't check balance prior to delivering the vehicle, only tire pressure", so I was told. Re-balanced, no charge of course, but the noise persists.

Anyone with a similar problem? Thanks.