SYE and CV dS

i'm getting a lift soon and want do do a sye and driveshaft rather than bandage up the old system. I've been looking at the RE hack&tap from jeepinoutfitters and was hoping someone who knows better could help me out..
is this a good way to go?
easy to install?

also what parts do i need that aren't in the kit (RE never really includes everything from what i've seen) and i've heard people saying theres an extra flange you need to buy for a 96+

this is probably a dumb question but every lift needs a different length ds? so if i do this lift and want to add shackles or something later i have to get a new ds?? dont like the sound of that

i've searched alot about this and found out alot of answers but there are some specifics i'd like to clear up before paying money

Its a good way to go if you dont want to open up the t-case. Its a money savings if you have a 96 or newer, if you have an older XJ, its not much of a money savings.
The kit comes with everything that is needed to install the SYE, doesnt matter what year you have. There are no extra pieces that you must purchase for the H&T SYE itself. Depending on what DS you use, you may have to buy a flange to mate it to the SYE though.
Two piece driveshafts with a slip shaft generally have enough travel that you can get by with the same shaft if you add a couple inches of lift, but that depends on how long your shaft is and how much lift you have.