Possible New Buyer - Help? Questions?

[iacas]

The gas consumption worries me, but I may be able to look past that if I like some of the other things. My current SUV gets ~30, after all.

I guess the rear seats can't be removed, can they? Hrm.

It has a bit more power (as far as horsepower) as my Aztek, but weighs a bit more, so I am guessing they'd be about the same. I don't need to tow anything huge, but I'll get the towing package to have the option. So if it's got enough power to tow stuff, I'm sure it has enough power to go for me.

My wife and I will use the Aztek for anything over 45 minutes drive.

I have two slightly more specific questions:
1) What questions should I ask the dealer?
2) What's included in each of the packages? The Hummer site doesn't quite list everything. I want the bigger wheels, I want the 7 speakers, but I could care less about leather seats (they're heated, though?) and the 6-disc changer - I've got an iPod for that. Is there any place that lists the differences between each of the three starting models?