i have a zj pitman arm on my xj. it does serve as a "drop pitman arm." i believe the wj pitman arm is more shallow, or not as much drop as our stock one.
to remove the tie rod or drag link you could use a two arm pitman arm/ tie rod end puller. DONT USE A PICKLE FORK!! at least if you want to reuse the end- it will tear the boot of the end. or you could take the castle nut off, turn it arround so that the castle end is pointing to the joint not the end of the threads to where it is just a little above the stud. then whack with a hammer. works well for me- i use either way
handles it fine. may of us here have done the ZJ rear disk upgrade, myself included. some have also swapped in the zj proportioning valve as well and we are pleased. some have not done the p-valve and they like it too. some say to get the full effect you should do the disk brakes, zj prop valve, and dual diafram booster. i love my rear disks