just found that a lot of my road manner problems that I had when I removed the track bars and sway bar, magically went away when I went back to stock height shackles. the shackle lift was on the jeep when I bought it, so I'm not certain how much of a difference the shackle lift by itself made, if the track bars and sway bar had been left on
just my opinion, I'd rather do 3" of body lift than do any shackle lift
oh yeah, the other thing I've noticed about shackle lifts, is that springs wear out and bend, and "invert" a lot quicker