Originally Posted by phunk

Each manufacturer, and often each specific model, uses their own proprietary IRS with entirely different geometry and behavior. A vehicles individual IRS specifications can make it greatly more or less suited for applying big power to the pavement.

Its a difficult debate to stay in very long without both cars side by side for measurements and testing... but you can expect that the Corvette IRS had typical Corvette power in mind during its engineering, and that the 370z had typical 370z power in mind. I would be surprised if the Corvette doesnt have a more longitudinally rigid IRS, along with quite a bit less camber gain on compression.