It's not at all that hard. You just turn the wrenches to lower or raise the stance, and that's it. It's better if you take the wheels off to do it though, since it'll make it easier to get to the shocks.
If you do get coilovers, if you have the patience to save for it, or if you have the $$$ for it now, get true coilovers (all in one shocks/springs) as they will give you a WAY better ride feel and look than sleeves like Drope Zones or Skunk2's will. If you DO go coilover sleeves, then you can't beat Grond Controls.
I have Tein "SS" coilovers myself on my ride, I was originally going to get Grond Controls, but I grew some patience and decided to do it the right way, and save a bit more and spring for the Teins instead. I'm SO glad I did. The ride quality of them is almost unmatchable, I can tune them from stock feel, to rock hard stiff feel in a matter of seconds using the supplied allen key that comes with them.
Good luck with it how ever you go with them.