The spare tire wheel isn't deep enough to accomodate a full sized tire.
If you get a flat tire with the michelins, don't buy a replacement mich. Instead replace all four tires with better all-seasons like the Falken ZIEX-512's.
Not only will it be close the price of replacing a SINGLE mich tire (most high performance (aka better then stock) tires are around 80-90 each), but you'll decrease your braking distance, increase your lateral traction, and your dry traction to boot.
Mich's aren't very good tires. The reason they are so expensive is because mich sells them to the dealers for almost nothing (which is why they use them) they greatly overexaggerates the price when replacements are required, making back their inital investment.
Unfortuantly many people don't realize this, and end up paying 3x more money for an inferior tire =/.