Here is my setup.

2000 XJ.
4.5" lift with adjustable upper and lower short arms
Adjustable track bar.
33" BFg km2
SYE
Tom woods rear driveshaft, stock front shaft
Dana 30 low pinion

I just got through adjusting my control arms so that my caster angle is correct. It drives 100x better than before. However I cannot tell if I have driveline vibrations. I don't think I should. I shimmed rear axle properly, have a sye. It's been so log since I've driven my XJ I cannot tell. It's always been noisy. It does t shake or vibrate violently at any speed. But between the 4.8L stroker ad all the other stuff it does vibrate (just combination of tires and engine I think) just going down the road.

 

i have a 4.5 lift and i didnt get vibes at all untill i changed my gears from 3.07 to 4.56 which made my ds spin much faster and not i get bad vibes it feels like ur tail end is shanking its not violent shakes its just an exxtemely fast vibration that notmally makes the center console and dash all shake around too and make noise, atleast in my jeep

 

Take it for a drive and use a cam to see what's up: