The 4x4 disengagement thing will not be helped by adding an SYE kit (at least not that I have ever heard of or can see how it would). Mine does that too sometimes, I simply stop, back up a little bit in reverse and then drive forward, pops right out. Same thing, not all the time but once in a while.
The SYE will completely remove all vibes and drive-line noise. This appears to be the Advanced Adapters HD SYE and the Tom Woods DS. Both are top notch components. I have had the AA SYE for 4 years now, works amazingly well and is well worth the money/effort.
If you want to go cheaper, you can grab the AA SYE and a front driveshaft (double cardan style) from a 4WD Cherokee XJ and use it as a rear shaft with this SYE. I did that, and have picked up a spare, so I have 3 identical drive shafts and I got both for $100 bucks.