I certainly agree with you comments on chassis stiffness. A lot of research into vehicle dynamics went into this program during development and I can honestly say that not one of the sources I used said the way to better performance was to reduce chassis stiffness. They all state and provide examples of how to increase the bending and torsional stiffness.

The other problem with using chassis stiffness as a tuning tool is now you have essentially added another spring into the suspension. A spring with no damper (shock) to control the response. That's like saying take all the oil out of your shocks and see what happens.

Personally I don't play around with chassis stiffness so maybe I am wrong. We already have more adjustability than full scale race cars so that's enough to keep me happy.