If you bought a decent lift, it should come with shims for the rear springs. The shims go between your axle tube and your spring and should tilt your rear end so that the ujoint angles won't bind.
You do not want to shim the front though. I had a 79 cj7 and had to shim the rear and drop the trany crossmember. All the tcase member drop is, is a 1" spacer between you framerail and your crossmember. you could use 1" square tubing for the tcase drop and do it yourself and save some cash. I bought my tcase drop, and it looked like someone took a peice of pipe about the size of a broom handle and cut it into 1" sections, I thought I could have made this better myself. To add to the longer shackles debate. When you add longer shackles up front, it tilts your front axle which affects your steering and also makes your ujoint angle up front worse. This is why people say to stay around the 1" length if you get longer ones, anything beyond that and you can start having problems. If you are looking for a little extra lift when you add your suspension lift, I think you would be better off adding a 1" body lift. If you go bodylift, stay below 3" or you can run into problems there.
