I've decided to stay with the stocker 235/75r/15 tire and have narrowed it down to 4 alternatives:
Michelin LTX MS2 = highly recommended by everyone. Perhaps the best tire on the list. 108T rated tires with a UTQG rating of 720AA. Treadlife warranty of 70k. Really nice tire for the Ex and the kind of driving I'm doing. Sams has them on sale Memorial weekend for $118/tire. I've seen them as high as $209! Not as aggressive tread as the others so not really an off-roader.
Thems the choices. What do you all think? I'd like to buy them from a shop that has them and just have them mounted/balanced right there than order them and have them delivered, etc..
The Michelin LTX M/S2 is a no-brainer, since you can get 60,000-100,000+ miles out of them compared to half that or less from the others you're considering and they are decent off road, even though they are not an All-Terrain. Bear in mind that they are a P-rated passenger tire and not a true LT Light Truck tire anymore, but they do have an XL load rating and a 50psi maximum pressure so they are about the same thing as the LT235/75R15 but better for road use, with a nylon cap and top A/A UTQG traction and temperature ratings. Only bad thing about Michelins seems to be they sometimes get cracks or the tread will chunk apart in small pieces, either from a lack of quality control or just mistakes in the manufacturing process.
They are a good deal from Sam's with a decent price when Michelin is having the $70 instant rebate, but they are an even better deal from Discount Tire with free mounting/balancing and a $100 rebate.
I know you said you already decided to stick with the stock 235/75R15 size, but just wanted to let you know other reasons that's not a bad idea. Besides the extra cost of 31's, they weigh quite a bit more anywhere from 7-11lbs more per tire, which adds a lot of rotating weight and makes acceleration slower and uses more fuel. You lose a lot of money up front when buying them and over the life of the tires in lower mileage, all for about half an inch or less in actual added height. You could turn them with the SOHC and the 3.73 rear for sure, but it's really not worth it for a vehicle that drives on pavement 99% of the time. You should be happy with the performance in the wet and snow with the LTX M/S2, not to mention the ride quality and handling/braking ability once at the proper psi.
As for the spare, it's usually not an issue, a 31x10.50 can fit fine depending on the brand and diameter, if it barely fits then some people just deflate a little so it squeaks up in there, and carry a portable compressor to inflate it should it need to be used.