but I've seen Porsche guys weld in steel bars going from one side of the chassis to the other. You may want to look into that. Then again a rollcage would probably be stiffer than a single bar.
"Losers always whine about doing their best, Winners go home and screw the prom queen"
-Sean Connery
"The sports car's sole purpose is to entertain the driver, and one very lucky passenger."