Have you seen these T-Bars? My brother ran them on his pathy when he put a aftermarket bumper on it. They kept the front end from sagging.
https://www.4x4parts.com/nissan/hardbody-torsion-bars-p-96.html
Also check out their lift control arms, I think what they do is lower the balljoint mounting point to lift the vehicle, but if you were able to flip the control arm, effectively raising the balljoint mounting point it would lower the vehicle, right? I haven't looked under a D21 in a min.