Just to clarify a few things...
The "slip yoke" is, as you know, the internally-splined tube that goes into the back of the transfer case. If you're going to put a SYE in, you're going to get rid of that attachment (Slip Yoke Eliminator.) This means that you're going to have a yoke a lot like you have at the rear axle, on the back of your transfer case (probably more like that for the front output, but you get the idea.)
No matter what you do, you're going to want a new driveshaft when you do an SYE. Not only because of the attachment change, but because you're also eliminating a "self-adjustment" point - you'll have to put a splined slipjoint in the middle of the shaft - so you're rear driveshaft is going to end up like your front. The principal difference? You won't have the double Cardan joint in your rear - unless you really want it.
If you get a hack & tap (or any other SYE,) you've solved one problem - driveshaft bind. You aren't doing anything to solve another problem you can run into - U-joint phasing. Let me elaborate...
With Cardan joints (the regular "cross" style joints we use,) the driveshaft actually speeds up and slows down infinitesimally, when the joint comes into play (when the shaft is bent through a slight angle.) How much depends upon how much the shaft is bent - but that's the source of vibration.
U-Joint phasing consists of two main parts - first, both yokes (and therefore joints) need to be aligned so that the "crosses" are oriented the same way. Make a shaft with the cross like + at one end and x at the other, and there's nothing you can do but start over. Both ends need to be + & + - no misalignment.
Second, and just as important, is that both joints have to go through the same angle when bent - just in opposite directions. Therefore, if the driveshaft is DOWN eight degrees from horizontal at the top, it needs to be UP eight degrees from horizontal at the bottom. This can be mitigated somewhat by using a "double Cardan" joint like on the front driveshaft - the two joints in the thing will ALWAYS be directly opposed. However, you'll want the centreline of the driveshaft to be common with the centreline of the input yoke on the axle, or you'll get vibrations anyhow (because there's nothing to "iron out" the vibes from that joint,) unless you go with double Cardans at both ends.
It's theoretically possible to get your new driveshaft with an extra-long slip joint - this should eliminate the need to buy a new one when you lift. However, driveshaft angles are still at issue - you're likely to need tcase lowering &/or axle "degree" shims to level it out. Unless you go with double Cardans at both ends - and even then, it may still be an issue.
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