I have 92 XJ I'm putting 4.5 lift on. Couldn't I put wedge in rear end and make new drive shaft in place of SYE kit? I've changed. Angle of rear end and made drive shafts for lots of drag cars. (I know jeeps are different animals) is it stronger with SYE kit. Don't mind spending cash if it is.

 

It wont be stronger than a good HD SYE with an extra roller bearing. Main issue with stock type rear DS is that the output shaft of the tcase has to support the weight of the DS. Not too big of a deal at stock height because the ujoint angles are not extreme and putting extra force on the tcase. I personally ruined my tcase output bearing from being at 5" in the rear with stock DS

Cheap option is a hack and tap kit and put a front driveshaft in the rear. Or you can put yours together and find you dont have vibration issues and maybe a little longer DS is all you need. All depends on the vehicle

 

you only solve the angle at the rear by changing pinion angle. the angle at the case is still the same, well close anyway. the idea is to use a double cardan shaft and spread the angle of the joint at the t-case over 2 joints, thus cutting the single joint angle in half.
Then you can shim the rear, and make sure the the pinion and shaft are inline.

 

Man that answered what I was getting at. One more question: I would need to use a new DS even with the SYE right? One that is able to slide in and out. To allow for suspension travel.

 

correct