I've never used the Superchips programmer, but I recently used a ProCal and it worked like a charm. I measured the height of the tire to the nearest quarter inch, set a couple of dipswitch settings on the ProCal, plugged the ProCal into the Jeep, and waited for the horn to sound telling me that everything was set. The whole process took less than 5 minutes.
Also, what everyone else is saying about tire size is true. I installed 35" tires and they only measure 34". If you don't measure the tire and only go by the manufacturer's size, that could throw off the speedometer when it gets programmed.