Torque Boxes vs. Frame Connectors

On another thread someone suggested I consider adding torque boxes or subframe connectors to my car. It made me start to think about whether or not a person needed both or if the subframe connectors would negate the need for the torque boxes. Is one superior to the other. I assume that Chrysler did not tie the frame rails together because of the unibody mind set. - It would have probably sent the message to people that the unibody was weaker than a full frame.

Do the torque boxes actually reduce the amount of twist to the body or do they just strengthen the areas where the leaf springs attach?

Frame connectors? Welded in,please... Some simple box tubing notched, works nicely......