THE theory sounds great - take a big, brawny rear-wheel drive sedan like the Commodore, boost its already powerful V6 engine with a supercharger, match it to a sports suspension set-up and you've got instant thrills. That's the theory behind the Commodore S supercharged, anyway. But these days the reality falls a little short, not so much because this car has sat still, more because others - most obviously Falcon's XR6 - are moving forward more quickly. In its latest VY Commodore guise, the supercharged S gets a significant exterior and interior makeover and minor mechanical improvements, but continues to be offered only with the ubiquitous Holden four-speed automatic gearbox.