If you look on eBay I think there are a couple of dealers in the Dallas area who frequently list 911s. These are not Porsche specific outlets, but they may have the inventory to allow you to test a wide variety.

 

Buy the newest Porsche you can afford. It's advice regularly given, and for a reason. Porsche continually improves the cars. Newer will always be better. That being said, I'd get a 4wd version in Michigan, or anywhere (contrary to advice up the page.) I've had 2 4S here in Florida, and there are many reasons to have one outside of the snow belt.

 

Also, be sure and check out RAC in Addison/Carrolton. They usually have some clean 997's with a manual tranny. Great folks there.

 

I always been told buy the newest you can afford.

As for AWD I think it is a personal thing and not necessarily down to needing it during the winter. I have a 2 wheel Carrera S and don't have actual experience with the Porsche AWD, except for a Cayenne S we owned and that's a different critter altogether. Drive a few and buy what makes you happy.