Both boxes use the same recirculating ball system and grease does a better job of lubing everything because it doesn't pool in the bottom of the box. All the imprtant parts are in the top of the box, so oil does no good unless it is being pumped through the box to keep it full. The manual box is supposed to be packed full of grease so it circulates as you turn and keeps everything in tip top shape.
I took the power box back and got the manual box. This is the one I modified for the pitman arm. I drove it today and the steering is many times easier than it was with the power box. 6.5 turns lock to lock. The heavy front end clunking is gone and the truck doesn't wander all over the road. I can turn the wheel all the way with one hand while sitting still. Couldn't do that before.
It takes a little while to get used to the extra turns on the wheel, but it is quite nice once you get used to it. It will be easier to eat while driving because it takes close to a 1/4 turn to get into the other lane.
I am not saying eating and driving is good practice, but there are times when it is necessary.