Sub Frame connector conundrum

This whole issue was addressed here a couple of days ago in another post, apparently not successfully.

As for differences between the various types and installation techniques, the real issue is corner to corner torsional rigidity.

Attach the front and rear subframes to a box girder structure (rectangular tube connector) and you end up with what is effectively a full frame independent of the passenger compartment box. Weld that connector continuously to the floor of that passenger box and you produce a far more rigid structure because you greatly increase the ability of the floor to resist distortion and are able to utilize the passenger compartment as a structural component (that six sided box thing again). Tie your added in connectors to the sill boxes that run between the wheelhouses under the doors with torque boxes and you increase it further. Triangulate the two smaller boxes (engine box and trunk) the front and rear suspensions attach to with additional bracing to prevent their distortion and you have just about a rigid a framework as you can get to keep the suspension attachment points in alignment short of installing a tubular space frame (read cage).