Maybe not, but it's been working for me so far. In my last race, I improved my over-all pace by three laps. I find that the minute amount of torsional flex gives me a more positive feel when cornering aggressively... or maybe I'm just wierd.
I just remembered... when mocking my diffs on the basic bottom deck I've already cut out the basic shape of, I tried flexing it up and down and even gently twisted it. It seemed to be fairly close to my current carbon fibre chassis, so I'm pretty confident that once the top deck and spine board are made and installed, it should be stiff enough for my purposes.
If it's not... I'll turn it into a drifting chassis. ;D