Take one 2006 Porsche Cayenne Turbo, add horsepower and torque, fortify the suspension and brakes, tweak the styling and trim, and you’ve got the new benchmark for performance SUVs: The 2006 Porsche Cayenne Turbo S. Perhaps best of all, you don’t have to trade off-road prowess for on-road performance, because, with the right set of tires, a Cayenne can bash boulders as well as most SUVs.