Torque boxes and frame connectors. When are they required?

Wouldn't that drive shaft length be wrong anyway ? If you'll need to have on shortened you may as well buy a heavy duty shaft to work with.
And as for unibody strength... many performance models and every vert came from factory with torque boxes.
I haven't seen bolt in torque boxes. The bolt in subframe connectors stretch the bolt holes over time.
There are torque boxes and connectors that don't require cutting the floor. All welded in. U. S. Cartool is one.