EVERY time Porsche rolls out a Turbo model — a designation that can now be found in the 911, Cayenne and Panamera lines — it’s clear that Stuttgart is pulling its punches. That’s because the latest Turbo is inevitably followed by the Turbo S, an even faster model that unmasks the Turbo as a sandbagging back-of-the-classroom slacker. Turbo, why can’t you be more like your brother, Turbo S?

In keeping with the tradition, the Panamera Turbo S is like a Panamera Turbo that’s having a really good day. The S is a little bit brighter, a little bit sharper and a lot more expensive. Revised engine management and upgraded turbochargers bump the horsepower rating to 550, from 500, while the peak torque rises to 590 pound-feet from 568.

Porsche actually quotes two torque figures, one of them the all-day-long-on-the-autobahn number, and the other the “overboost” torque that’s available for temporary sprints and pulling stumps back on the farm.

I referenced the higher number because it seems more likely that you’d indulge in temporary full-throttle situations than constant-load slogging. But if you manage to bolt your Panamera motor to the propeller of a medium-size Louisiana shrimp boat, be aware that constant maximum torque will be only 553 pound feet.

In terms of outright capability, the Panamera Turbo S is on the extreme end of the sports car spectrum. Porsche claims 0-to-60 acceleration in 3.6 seconds, which puts the Panamera in roughly the league of the Chevrolet Corvette Z06 and the Audi R8. That’s decent company, considering that the Panamera is a four-door car with 44.1 cubic feet of cargo space. (For comparison, that’s within a couple of cubic feet of the cargo bed of a Cadillac Escalade EXT pickup truck.)