S197's don't need subframe connectors in the least. The main tub is a BRICK! I know of 3 4100lb GT500's that can run in the 9's if they want too and none of them have subframe connectors.
At least one of the three was running in the 10's, pulling the front wheels and weighs 4350lb with driver and he ran no cage and connectors for a while.....till they wouldn't let him run that fast anymore without a cage.
The car never had any of the chassis twisting issues seen with past gen cars (broken windshields, doors that wouldn't shut right, rattles, uneven body seems, etc).
I've put my car on jackstands (under the main tub) and set it up so they were at slightly different heights (slightly, as in 1/4"). The chassis did not flex at all. I could rock the car from stand to stand by hand. You wouldn't have been able to do this with a pre S197. It would have flexed enough to contact the "lower" stands.