OK, looks like the e-mail I sent had the right effect. The service manager got involved, they will replace the 2 rear Michelins at their expense. I told them I want the new rear tires examined with a fine-toothed comb before they mount them.

I am also trying to get FULL CREDIT back for the left front, which they replaced earlier today. I told my SA that I do not buy the road hazard argument for that 1 new tire, when the 2 rears also had cracks in them. Funny enough, he's still resisiting me on that, claiming I must've hit a pothole. Anyway, he's going to talk to his service manager about it. I'm not letting this one go. I should not have to double-pay.

I guess the bigger question is: where did they get these tires from?? Now he's saying they came from BMW, which is like saying cow's milk comes from the supermarket.