Porsche Panamera ST: a luxurious ride with the 'vrrr pha' of a sportscar

Hold on just a minute. Why does this Panamera look different to the one my brother-in-law drives?

That's because the one I'm piloting here is the new (well, newish) Sport Turismo version. The Porsche engineers have extended the roofline, put in a more steeply raked (and electrically powered) hatch and in doing so have built one of the coolest shooting-brake-cum-station-wagons the world has seen in ages.

This makeover gives you about 5% more boot space plus a much-reduced lift over height: a real godsend if, like me, you're cursed by lower-back issues and usually travel with lots of paraphernalia.

Added practicality aside, the Sport Turismo is a stroke of genius because - at long last - it finally gives the Panamera an identity. It has ditched that awkward red-headed stepson image and evolved into a cool and confident individual, marching ahead with a slightly left-field swagger. In fact, it's a mystery why Porsche didn't do this from the get-go. 

I'll concede it's a fine-looking motorcar. It does look heavy though. I trust it comes well-endowed in the engine department?

The Sport Turismo currently comes in three flavours of driving spice: the mild 4, medium 4S and fiery Turbo. I sampled the 4S over seven days and across nearly 3,000km of grizzled South African road and it is, quite frankly, the one you want. It's what we hacks call a Goldilocks car: not too little, not too much - just right.

There's a twin-turbocharged V6 motor under that lengthy bonnet and it gives this Sport Turismo some serious kick. Quick off the line (all-wheel drive and an eight-speed PDK gearbox make sure of this). It's also got some serious highway legs. It was born to devour long stretches of freeway and sits comfortably at 200km/h when most cars have run out of revs or blown a gasket.

Feel like testing that rolled up bundle of bribery banknotes in your glove compartment? I did, trying to escape the dream-shattered horrors of Molteno in the Eastern Cape, and hit 262km/h without any protest. This is a supremely fast piece of equipment.

It sounds good too: touch the sport exhaust button and your ears will get treated to a lovely, sharp-edged V6 wail.

I assume this machine was built to take on the BMW 7 Series and Mercedes-Benz S Class. Does it stack up?

You assume right. In terms of space and grace the Sport Turismo is every bit as capable as the more established BMW and Mercedes. Except the Porsche is way better to drive because beneath all that luxury beats the heart of a sportscar.

Speaking of luxury there's not much Porsche has left to desire - especially on the technology front. Taking centre stage is an excellent 12-inch infotainment system that's intuitive to use and gives you snappy access to everything from Apple CarPlay and satellite navigation to drive settings and audio customisation.

You also get a fancy piano-black centre console peppered with futuristic "haptic" feedback buttons that control many of the car's other features (heated seats, ventilation etc). Comfort levels are high - I took this car on a road trip with two other dudes and none of us felt that there was a lack of leg, head or shoulder room. Yep, even when sitting in the back, which, incidentally, has its very own console for climate-control settings.

What really impressed me, though, was how well insulated the Sport Turismo is. Even at high speeds, wind and road noise levels are breathtakingly low - important in a vehicle built to traverse long distances.

I like road tripping, but wouldn't something like a Cayenne be better in a country with lots of dirt roads and bumper-scraping obstacles?

I was worried about that too. Our excursion took us through the Eastern Cape and some of our destinations could only be accessed via gravel roads peppered with speed bumps and other irregularities.

Fortunately the 4S comes with a trick air suspension system that can raise the car's ride height at low speeds. Not enough to turn it into a rally car, mind, but enough to alleviate your stress about scraping the underbelly or front apron.

On the flipside, this system can also lower the chassis at higher speeds to increase stability and enhance handling.

Speaking of handling, you mentioned that you were impressed, right?

Yes, very much so. The Sport Turismo is a hefty machine with an unusually long wheelbase, yet it still managed to tackle the squiggly, high-speed curves of the Lootsberg Pass (and other great passes for that matter) with all the poise of a much smaller sportscar.

Lower the suspension, stick everything into Sport Plus mode and this Porsche immediately hunkers down and sharpens up. It disguises its weight tremendously well and consequently you enjoy the driving experience way more than you would in those aforementioned BMW and Mercedes-Benz rivals.

It also demonstrates prestigious grip on the limit: most welcome in a machine that weighs close to two tons. Choose to take it slow though and the Sport Turismo will oblige with a ride that's smooth and supple but never vague or overly floaty.

It's a class act: a faultless merging of all disciplines into one striking and devilishly efficient product offering. So could this be the best sporting four-door luxury vehicle on the planet? I think it may just be.