What is it? It's the most powerful version of Porsche's four-door grand tourer. On sale now, the Turbo S isn't just faster than other super limos such as the Aston Martin Rapide it's faster than many full-blown supercars.
What's it like to drive? The 543bhp 4.8-litre twin turbo V8 shrugs off the Panamera's two-tonne bulk to give a 0-62mph time of just 3.8 seconds. That's quicker than an Audi R8 V10.
Just as impressive is how the Turbo S makes this performance so undramatic. Even on a wet road you simply plant the throttle and the four-wheel drive system ensures that you're fired at the horizon without any fuss.
The Turbo S isn't all about straight-line speed, though. Yes, it can hit 190mph, but it's also astonishingly agile for such a heavy car. It turns in eagerly and combines immense sideways grip with very little body lean, so you have the confidence to really attack corners. In fact, if we have one criticism, it's that the Turbo S is so unflappable it leaves you a bit removed from the driving experience.
If you're planning to use the Panamera's mile-munching abilities to cross continents, you might also get a bit fed up with stopping for fuel. The Turbo S has a huge 100-litre tank, but an average of 24.6mpg gives it a theoretical range of only 540 miles. What's more, you won't get anywhere near that if you're pushing on. The diesel version of the Panamera, on the other hand, can manage 43.5mpg, so has a range of over 750 miles.
Leave the car in 'Drive' and Porsche's excellent seven-speed PDK twin-clutch gearbox flicks through the gears automatically. Alternatively, you can take control of changes using chunky steering wheel-mounted paddles.
What's it like inside? The Panamera mightn't be conventionally beautiful from the outside, but the interior is simply stunning. The whole cabin is beautifully styled, while the materials and build quality are top-notch.
It takes a while to get used to the mass of buttons on the sweeping centre console, but that's more to do with how many functions are available than the layout being particularly poor.
The Panamera can seat four in luxury because it has comfortable seats and masses of legroom in the front and back. Access and headroom aren't quite a match for the biggest luxury saloons, but the Panamera still has proper limousine credentials. The boot is big, too, if a little shallow.
To go some way towards making up for the huge price, the Turbo S has loads of kit, including 20-inch alloys, a 14-speaker BOSE stereo and Porsche's Vehicle Tracking System (VTS), for added peace of mind.
Should I buy one? The Turbo S is staggeringly quick and immensely capable; no other super-saloon can match it for outright pace. However, the standard Panamera Turbo is almost as rapid and costs 19,000 less than this S version.
Look outside the Porsche brand and there's also the Mercedes CLS63 AMG, which is more engaging to drive and significantly cheaper at 80,000.
So, although it's impossible not to marvel at the range-topping Panamera's abilities, there are cheaper ways to enjoy this much luxury with almost as much performance.
What Car? says