Torque Box Questions???

Moving the springs to the frame does nothing to improve the stiffness of the chassis. The torque boxes aren't there to back up the spring mount, they box the connection between the rockers and the frame rails. Boxing the corners significantly improves the torsional rigidity of the chassis. Take a look at the front torque box. No suspension mounts within a foot in any direction, and yet they still improve the chassis.

The rear torque boxes will work just as well with the spring relocation because they're boxing the connection of the frame rails (which now house the spring mounts) to the rest if the chassis.