I agree with Jeffy, stacking big lifts is not a good idea.
However, I come from an area where the bigger the better and it is not uncommon for a jeep to run 38's and bigger. This is not just the mere stacking of lifts. The axles will need to be at least 3/4 ton and most go 1 ton. You'll need to cut and turn the front axle, careful not to **** this up. The four banger is definitely out of the question, which makes more driveline issues. Most would go with a SBC 350 /t350/ np205 or atlas for the shortest driveline. If your an AMC engine fan it changes to 304/360/401 motor and most likely a t-18 with a Dana 300. By your name I can hazard that your leaf sprung. That makes this a bit easier. If your in a TJ gettting the kind of lift your talking about takes custom brakets and trusses.
Yeah, you may not need half of what is in the kit, but if your stacking on top of your existing lift, you'll probablly need 10 times more.