Subframe connectors/torque boxes question

Subframe connectors and torque boxes act in different places and do different jobs. One does not replace the other. Torque boxes tie the frame rails to rockers, and box the leaf spring mounting area in the rear which increases torsional resistance. Probably more so than frame connectors alone. Which is why the factory used torque boxes but didn’t tie the frames together. They were designed to strengthen the corners of the box, which is why ‘verts got them.

That’s not to say that the addition of torque boxes eliminates the need for subframes either. They both can significantly improve chassis stiffness. Especially at the rear of the car where the torque boxes can spread the load of the subframe connectors out from just the rear rails.