Porsche Panamera Sport Turismo

The head-turning Porsche Panamera Sport Turismo, which, officially at least, is still a concept. After all, why would Porsche build a road-going concept of a car it has regularly hinted at and revealed to the public if it hadn’t already made a solid case for production?

The Panamera Sport Turismo drips with desirability. It is truly handsome, boasting terrifically low, wide and squat proportions, with a long bonnet, tapered glasshouse and muscular haunches.

The surfaces are tautly wrapped and full of intriguing feature lines to break up the visual bulk. At 4950mm long, 1990mm wide and 1401mm high, the concept is 20mm shorter, 60mm wider and 19mm lower than the existing four-door Panamera – dimensions expected to be retained for the production model. The wheels are 20-inch up front and 21-inch at the rear. It is, remember, a concept, after all…

The exquisite detailing stands out: the elliptical headlights, the thrusting side design feature and the slim three-dimensional rear lights help to enhance the car’s width. In a nod to the future, door mirrors have been replaced by cameras within the air ducts, with images projected into the outer edges of the instrument binnacle. 

The fully functioning concept also showcases a new plug-in hybrid drive system, dubbed e-hybrid. It uses a more powerful version of the existing Panamera Hybrid’s brushless synchronous electric motor, mounted within the forward section of the gearbox housing and delivering 94bhp. It is supported by the same supercharged 328bhp 3.0-litre V6 petrol engine used today.

Together, the electric motor and petrol engine provide the big estate with a combined output of 410bhp –sufficient to propel it from 0-62mph in less than a claimed six seconds, while providing combined fuel consumption of “better than” 80.7mpg and CO2 emissions below 82g/km. A 9.4kWh lithium ion battery mounted low in the boot floor replaces the nickel-hydride unit in the current Panamera Hybrid, and features plug-in compatibility.

Porsche claims an all-electric range of 18.6 miles at up to 81mph – values that are likely to be reflected on a facelifted version of the existing Panamera. It will be the first to adopt the new driveline. No wild pipe dream, then, but a genuine production-based driveline.

There’s a contemporary look to the cabin and inviting, iPad-like simplicity to the dashboard and centre console – both of which mimic the look of the 918 Spyder. There is little to complain about in the cabin of the existing Panamera, but its controls are dauntingly cluttered around the driver. The Sport Turismo showcases a simpler touchscreen system tipped to feature on future models. 

The layout gives an organised feel from behind the beautifully proportioned steering wheel, while leather and aluminium trims provide an upmarket ambience. Accommodation up front feels little changed from today’s Panamera. The rear is a bit more cramped because of the concept’s pair of large individual seats, while more cargo capacity is afforded by the more upright rear end. Porsche won’t yet reveal figures but there’s likely to be at least 500 litres – a 55-litre improvement on the liftback.

Before I get under way, the Sport Turismo needs to be unplugged from the charger that is claimed to be able to top up its battery in just two and a half hours. Tread firmly on the brake, hit the starter button and there's little in the way of aural excitement, just a faint whirring as the ignition is tripped. 

Even so, it's well mannered and genuinely fun to drive. You can whip it down the road with utter confidence, relying on the fluid actions and response that you might expect of a true production car. This is not something you could say of most concepts. The steering is nicely resolved, too: direct away from the straight-ahead and weighty as lock increases. It could use a little more low-speed feedback and a greater eagerness to self-centre, but the electro-mechanical system operates with conviction and precision.

The ride is a bit fidgety at low speeds, partly because of the lack of any real profile within the 265/35 front and 295/35 rear tyres. However, the car settles as speeds increase, and by the time we’re cruising it’s almost comfortable and the overall refinement is impressive. That said, the roads around our Beverly Hills test route are among the smoothest in America, so the fairly conventional steel-spring suspension isn’t overly taxed. The brakes feel over-servoed, biting hard within the first couple of degrees of modulation, but prove manageable enough. 

Despite its generous dimensions, the estate doesn’t feel oversized or ponderous. A rethink of the glasshouse brings shallower side glass, a larger fixed rear three-quarter window and a more heavily angled tailgate. Visibility is impressive, although this has more to do with the high-set driver’s seat than anything. Note for the production team: lower the squab and provide a more sporting driving position. 

Press the accelerator hard and when the turbocharged 3.0-litre V6 fires, it sends out an alluring cacophony of mechanical clatter and exhaust snarl as the car surges forward. The car may weigh close to two tonnes, but it doesn’t lack for pace. Six seconds for the run to 62mph? It feels faster. In-gear acceleration is equally as impressive.

You can't just yet, and Porsche says insists it isn't even confirmed for production. However, it’s not really a question of ‘if’ but ‘when’ the Panamera Sport Turismo will be built. The indications are that it will form part of a four-strong second-generation Panamera line-up, set to include liftback, estate, coupé and convertible models, and it is expected to reach showrooms some time in 2016. 

From what we’ve seen, the production car promises to be a highly desirable alternative to the likes of the Mercedes-Benz CLS Shooting Brake, Audi A7 and BMW 6-series GranCoupé. The price, of course, will be high – somewhere on the far side of £70,000 for the petrol-electric model, one could assume. And what if Porsche doesn’t build it? It will, believe me.

Porsche Panamera Sport Turismo

Price na; Top speed na; 0-62mph sub-6sec; Economy 80.7mpg; CO2 82g/km; Kerb weight na; Engine V6, supercharged, petrol, 3605cc; Power 328bhp (engine), 94bhp (motor); Torque 435lb ft (est); Gearbox 8-spd auto