It doesn't take much to hold seats in, it's the safety equipment (seat belts, harnesses, etc.) that needs solid mounting. Seems adding all that tubing is just added weight. Subframe connectors connect the front and rear subframes of a unibody car.
I should have been more clear, What I was wanting to see was others subframe connectors to see how they looked. So I could see about maybe tying my seat tubes to the connectors, later probably adding a 6 pt cage too.