Because the diff is dropped away from the frame, the angle of the shaft on the tcase side is greatly increased. This over time will wipe out the CV on the stock 98+ shaft. It's not a matter of if it'll fail, but rather when it will fail. I got 4k out of mine after the lift. The truck had only 70k or so when the lift went on.
The Superlift shaft basically is a 95-97 Explorer shaft that's been shortened, and an adapter attached.
There are alternatives to the Superlift shaft. You could swap in an older 90-97 BW1354 manual shift transfer case, and run a rebuilt 95-97 Explorer shaft. Or do what I did....got a NOS(brand new old stock) 97 explorer shaft, the exact adapter Superlift shafts have from Neapco, and a little shortening job... BAM! I have the $500-600 Superlift shaft for a grand total of under $300 using BRAND NEW PARTS. That's darn near what I paid for the Superlift! lol. You can do the same thing too using a 95-97 explorer shaft, rebuilding it, shorten it, getting the adapter, etc. Should run ya in the $200-250 range.