BillyBob, I followed your advice and drilled a 3/16" hole the axle nut and cracked the base of it with a chisel. It still took a lot of torque to break the nut free. Thanks for the tip. I spent hours wrestling with that damn nut. I can't help but think there is an auto worker somewhere in Germany still laughing about the nut he installed that had to have 200# of torque on it.
After that, I had the first axle bolted to the differential and realized that the new one had a gear pressed on the opposite end for the ASD, that was bound against the backing plate when I tightened the axle nut. So, out again to pop the gear off and back in. I also changed the subframe bushings, diff. bushings, sway bar links and LCA's to get the rear end to follow the front end. Fortunately, getting the subframe back in the car went pretty well.
Looking forward to a trip down the interstate to see if my hard work pays off.