My '04 330ci (with ZHP) has 32,000 miles on it now and the OEM tires have become quite noisy. The OEMs are Michelin Pilot Sport and I've kept them properly balanced and inflated. I travel Phoenix-Tucson regularly. When people ride with me, they think something is wrong with the car because of the sound, sort of a low pitch grinding sound. I'm thinking of replacing them even though they are not worn out with Michelin Pilot Sport PS2 (which has a different tread pattern). Has anyone had experience with PS2s? What are your suggestions? By the way, quality is more important to me than price. Thanks for your input.