A bit off-topic, but with a few others referring to rear gear ratios, I really don't understand how anyone tolerates driving any of these low-ratio rear-ends. In the last few years, 3.5's and even 3.2's(!) are becoming common, thanks to 8 and 10-speed transmissions and the endless hunt for better MPG's. But they drive like a wet napkin, I can't even feel the gear changes, due to the low separation created between each trans gear on such a low-ratio rear.
Trucks should really never have a rear end ratio lower than 4:1, and I'll continue to order them with this option as long as it's available, although presently 3.93 is as close as I can get in OEM. It gives better torque off the line when towing, wider separating between gears, and crisper gear shifts you can actually feel.
Also, for all the guys mounting big tires, I can't imagine doing it on less than 4.11:1. I think my last lifted truck (25 years ago) had 5.38:1 diffs.