I've been lurking for some time on this thread, obsessing about tires. For now, I want to keep MPG up and maintain the stock wheels, suspension, and ride, but with a more aggressive tire. I also wanted the largest tire that would fit without any mods, and that would fit in the current spare tire location. Yesterday, I had Discount Tire mount General Grabber AT/X 275/70R18 116S and am very pleased with the results. I notice very little difference in the ride, perhaps a bit more firm (which I think is good), and about the same road noise as stock (I have active noise cancellation and fake engine noise turned off). These tires are only 7 lbs heavier than the OEM tires. I also gained about 3/4" of clearance.