She's smooth as glass with the rear drive shaft out, and vibe city with the front shaft out, so I don't see how a front hub kit would solve my vibes. I'm still working on the theory that my operating angles have something to do with it. Why else would the vibes get better when I lower the t-case. That was how I decided to add a MML (Motor Mount Lift). I lowered the t-case skid 1", which gave me the biggest improvement. Why my jeep is so sensitive is beyond me. Your drive shafts think you have a 6"+ lift with your 4" springs and UCF TT, so I just don't get it. Heck, when I first lifted mine many moons ago, I had to lower the skid 3/4", and that was just a 2.5" lift. Add the increased RPM speeds post regear, and I have a recipe for a back massage.
I have it now where I can just hear it a little above 55 mph, and not feel it until 65mph. If I had the soft top on I wouldn't be able to hear it with the added noise level. Hard top seems to amplify it. Maybe I should sell the hard top and get a Bestop twill top and call it solved, lol!