**I posted here because this swap is applicable to most Jeeps with D30 front ends.**
I've researched this swap over the last couple of years, reading thread after thread. All of them state that the WJ knuckle has a different offset, so a spacer must be used to re-align the u-joint. I've found that's only half true. The spacer is only required to use the TJ/XJ 4.5x5 Wheel hub assembly as its much deeper than the WJ hub. The best description I being here
(Picture is below if you don't want to follow the link) - The internet can be misleading, after actually measuring the parts I found this to be untrue.
WJ owners often use the outer shafts from YJ/TJ/XJ's to convert their front axles to stronger U-joints over their CV axles (requires custom inner shafts)
So, why not go to the 5x5 bolt pattern and use bolt on Brakes?
(steering/track bar solutions aside)
With the JK running 5x5 wheels now, the aftermarket selection has greatly increased. Cheap JK take-offs are incredibly abundant, especially on Craig's List. They give you 32" tires and 16"+ wheel you'd need to fit the larger caliper w/o any grinding.
Obviously you'd have to change out the rear lug pattern, as well. You could use wheel spacers, re-drilled axles & rotors, or even get away with the WJ rear disc brakes!
Unless someone talks me out of this, I think I'm going to give it a shot. My Rubicon may be a prime candidate, as I think there is a good chance the WJ's rear brakes will bolt up. The local Pick & Pull has a few good donors lying around with Dana 44's in the rear to match mine. I've got my own thoughts on the track bar/Steering situation, I'll save those for another thread. What's your opinion on using the 5x5 wheel pattern all around?