if you've never done it and your first time is on the trail... i'd give yourself an hour at least because nothing will go just right. its not hard to do, but you have to remove a few things first including the 200+ ftlb spindle nut. 32mm socket, breaker bar, loctite, 15mm or 1/2" (can't remember) for the pinch bolt, 1/2" for the shock bottom, whatever the top is (it can be removed without taking the shock off though), wheel bearing grease, jack, elbow grease, big screwdriver or pry tool, new gear lube (if you spill any out of the diff), curse words. that's about it i think. keep in mind i'm not mentioning the stuff needed to remove the caliper assembly and bracket and rotor.
look at the writeup jefe did about installing the front locker in the "useful threads" forum. it has the steps to remove the CV passenger side and is a great writeup. you'd just do the same for the driver side..
the flex difference is minimal. the ride is much better.