I've had the XPS ribs on the rear of my 96 dually for two and a half years now. They are excellent. Run them on two Alcoa's and two stock steel on the inner rears. Have not rotated or had to rebalance in +40K miles with even tread wear.
I run smaller size (225-75-16) than stock for increased gear ratio and it also lowered the truck 1 inch from what the 236-85-16 tires did. I also run at 70 psi.
I have LTX M/S on front that I bought 3 months earlier than the XPS and wish I had the XPS's.
don't knwo exactly how much I paid because it was a package deal, mounting / dismounting 6 tires, 4 new XPS, valve stems, McGard Chrome lug nuts, McGard Chrome Locks, front and rear Alcoa center caps and a lifetime road hazard / rebalance from Discount Tire. It was a good deal though I do remember that.