42RH / A-500 in a Duster with pictures.

If you have subframe connectors there is an easy fix for this concern. Just triangulate the torsion bar crossmember into the subframe connectors.

See that plate running side to side on the front of my trans mount crossmember? 1/4" plate steel, that sucker isn't flexing anytime soon. I tend to drift towards overkill when in doubt, I'm still going to add some small plates topside just to be safe.