On the issue of TTB tire shredding, I've had the same Goodyear Wrangler RT/S tires on my truck since I bought it, haven't rotated them once. In almost three years and 35,000 miles I haven't seen much at all in the way of tire shredding that so many others with the D50 axle have.
Last year I went through and replaced all the wear components, with the exception of pivot bushings (and I need those done too) There is exactly ONE component more on a D50 than a D60, and that is the inner passenger side U-joint. D50 has pivot bushings, D60 has track bar bushings. Everything else is essentially the same.
I am not in any way saying that having a D60 axle wouldn't be great. In my case I searched all over for one when my D50 needed repairs- each and every one I found needed most if not all of the same repairs done that my axle needed (ball joints, U-joints, tie rods, etc) Most had been cannibalized in preparation for Jeep installation, with spring perches torched off and such.
I am of the belief that if you rebuild your D50, with good parts, and take it in to a good alignment shop, you can get good long life out of your tires.