it doesnt matter about the keys. they are just indexed different. if u can allign it now it will allign with the lift kit on and the keys in the same position. mark the screws before u remove them so u will know about how far they were in.
people get it mixed up, esp these key manufactures they say "wont max out torsion bars, or wont max out keys" thats bs, its no different then cranking the stock keys to get the same amount of lift. it doesnt matter if the bolts are all the way in or just resting on the nut thingy. crank is crank.
the common misconception with torsion keys are people think they buy the new re-indexed ones and crank the piss out of it and it will ride like stock. which is not true, they are for the "dummy installer" u put them in and leave the bolt barely in, with the key resting on the stop, which gives u the amount specified. there is no turning and measuring to make sure u get that height. whereas stock keys u have to run the bolt in, let jack down measure and if not where u want it do it all again.
i put 97-02 f150 keys in my z71 2500 they were exactly the same as the suspension maxx and others. at rest the net about 2.5" lift. which was how much i had my stock keys cranked. there was absolutely no difference whatsoever. they would have allowed 4" of lift if i ran them all the way in, and guys were doing an upper bj flip, mounting the bj on the bottom to get it to allign.
sorry...anyways the 4" lift will be a drop down kit which uses stock torsion bars and everything. only thing is the mounting points for the control arms are lower(UCA"s would stay in place if its a knuckle kit) which has nothing to do with springs. ive installed about 10 torsion bar IFS kits at work and the owners wanted me to crank the bars about 2" to get more. one being a chevy with a 6" RC with 2" crank. s10 zr2 6" superlift with 1.5" crank. none had problems alligning, and i know this because i dropped them off at the tire store myself and got the allignment printouts