Just checked Costco's site here in Saskachicken. The prices were a bit higher than what Kal Tire quoted Mike and they didn't have the P4S in the front size.
I do find it amazing that tires crack and split just sitting without moving, but I guess they would be under stress still sitting on the car. Who knows what compounds Michelin has in their tires. I am hoping they don't crack as I have a set sitting on my car in -27C temperatures as we speak and the last half of this winter (As everyone knows except for you coastal folks
) has been freaking cold. I never worried about it before, but I usually had normal 'high performance tires' on my car, not these overly sensitive sissys tires that crack under pressure.
Oh, and similar to Graham, the last time I had my tires swapped, I did the same with just taking the tires and rims into Costco. I did ask, just to check, if they had experience with Corvettes, and they said they don't do Corvettes as they are too low for their lifts, which as nice to hear a shop admit their limitation instead of just pushing forward and 'making things work".