While I would love to go with an HD, the extra headache of using it as a daily driver in tight parking lots and airport valet just doesn't make sense. But I definitely want the 3.92 because, as it's been mentioned before, my truck needs to tow more than an SUV.
I spoke with my local differential shop and they have all but killed the idea of buying the truck without the must-have RAR. First, they can't order the parts so I'd need to get them from the dealer ($$$$ - don't forget it's 4wd). Second, even if I got them to throw in the parts on the purchase, it's 1k estimated labor. I guess the front diff is actually welded to the frame. He even thought they might have to sell me the whole FE assembly. I am waiting on the sales rep to check with their parts dept, but it will probably be cheaper to factory order.