So Costco can't get the Sport A/S in 225/50/17 (although I know Michelin makes them). Anyway, they do have the Pilot XGT Z4 for $191 each balanced & installed, plus $50 off a set of 4.

Anyone see a big diff between the Sport A/S and the Z4s?

The A/S is the all season version of the Z4 I think... If you don't need to worry about snow or anything, then I think the Z4s will be ok. They're supposed to be a higher performance tire (softer rubber I guess) and that's why they aren't the all season version.

Well everyone is trying to get rid of the Z4's cause they arent making them anymore (from what im told), so youll find some pretty cheap prices. The A/S tire will replace the XGT's. Id just cal around and see where you can get the A/S's. They are well worth the money.