I agree with Carl about the roll cage. Extending the connector past the torque box would not increase stability because that is where the frame rail gets its rigidity. If you want more strength for the rear frame rail a roll cage will have to be placed over the front and rear spring hangers as Guldstrand recommends in his TransAm Camaro Prep manual.
I switched from "shot" rubber bushings to connectors and solid bushings and the difference was dramatic! Pulling into my driveway the car would twist, squeak and moan. Now, no sound and the twist has mostly disappeared, much more rigid.