Both the dealer in Encinitas CA & BMW refuse to do anything re the very noisy 18" Potenzas on my 06 330i. Even though there is still about 1/3 tread left after 15k, the tire noise is almost unbearable. The dealer & BMW area rep refuse to do anything for me. All seem to agree that there is a problem (not with the car) but they refuse to do anything about it. All I'd like for them to do is prorate the tires and reimburse me for what tread life is left. I'd then take that bit of $$$ and buy Michelins. Not so sure about this Ultimate Driving Machine business. I'll keep plugging away and go to the next level.