Porsche Panamera Sport Turismo

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.