you can do it either way. the first time i took mine off the xj, wasnt too difficult but its alot easier leaving the main spring on the chassi cause the bolts can be a bit of a pain sometimes. you can leave the main spring bolted to the truck and move the axle (jack the truck up higher but don't over extend the brake line) outta the way so the other springs have room to come out ( i used 2 c clamps and slowly undid them) thatd be an easiest way i know. how much of an aal are you doing? i did what was supose to be a 2" but was more like 3". it was one full length leaf, rode like crap. if your only doing a 1 or 1.5 id look into shackles. i got some beefy rocky road shackles http://www.rocky-road.com/xjshackle.html