OME shocks are a bit longer than stock Trooper shocks, and are made to go with the 1-2" Trooper lift springs (912/919/929). Great shocks BTW, I have tried others but keep going back to OME.

But longer shocks are not mandatory by any means. A simple rear spring/spacer and front torsion bar lift doesn't change your range of suspension travel at all, you are just riding higher within that same range.