In a provocative move certain to not have been missed by its Bavarian rivals, Porsche staged the launch of its all-new four-door, four-passenger Panamera Gran Turismo right in the heart of Munich airport's busy business precinct, close to the corporate nerve centre of that other German performance powerhouse, BMW.

No doubt BMW and its German premium rivals, Mercedes Benz and Audi, will be watching with interest to see if there is enough oxygen in the current, beleaguered market to sustain a prestige performance vehicle that blends attributes of performance sedan, luxury limousine and sports car.

Classifying this, the fourth model range from the small but influential Stuttgart manufacturer is not easy, a fact acknowledged by Porsche Australia PR chief Paul Ellis, who helped coin the phrase "four doors, four seats, four-inches off the ground" when communicating the concept to potential customers.

A less generous description was offered by a British journalist, who described it as "big, ugly, but good to drive".

At the car's international launch in Germany last week, Porsche chief chassis engineer Andreas Probstle told Wheels; "We have no one main competitor, because the concept (of a four door, four seat luxury performance coupe) is still really new."

This much is certainly true, though claims that the Panamera is a genuinely unique concept might well be challenged by Mazda, which gave the world its four-door four-seat RX-8 sports car as far back as 2003.

Regardless, Porsche clearly hopes that the difficulty people have in placing its new GT on a positioning map will translate to an ability to cut across various sales segments. The company specifically mentions such super-sedan rivals as the BMW M5, Mercedes E63 and Audi RS6. But the Panamera also targets Benz's CLS 63 AMG, Maserati's Quattroporte, and the high performance variants of luxury limousines such as the Audi A8, BMW 7 Series, and Benz S-Class.

The Panamera arrives at a delicate time for Porsche; still embroiled in damaging fallout from its ill-fated Volkswagen takeover bid. Porsche board member for sales and marketing Klaus Berning pointedly refused to discuss details of that situation at the Panamera press conference, preferring instead to deflect attention back onto the new car.

Fortunately, regardless of how the political machinations of the VW/Porsche 'cooperation' play out, what is abundantly clear is that Porsche has delivered yet another brilliant sports car.

Two days spent hammering the potent new GT over the alpine roads that criss-cross the German and Austrian borders outside Munich confirm the Panamera as, quite clearly, one of the planet's finest GT cars.

It won't necessarily be the most attractive car in its segment though, and debate had begun long before the car's launch as to whether it is beautiful, handsome, or plain plain. A straw poll of Aussie journos at the launch seemed to indicate some consensus that the packaging and interior presentation of the Panamera are both first rate, but that the overall design may not be as successful.

It's the rear end that draws the most criticism, with not everyone agreeing on the merits of the bulbous lift back. The car is undeniably a Porsche, however, and design chief Michael Mauer spent his presentation outlining how the design team had attempted to incorporate such classic 911 elements as the pinched waistline, powerfully flared haunches, tapered glasshouse, and flared fenders.

Mauer's design brief called for, among other things, coupe-like styling with sports-style accommodation for four, Porsche driving dynamics, best in class performance, and good fuel efficiency. Individuals will be the ultimate judge of how successful the team have been in a pure design sense, but there's little doubt they've delivered on the rest of the brief and, in the process, created a car that is both interesting to look at and, unequivocally, a Porsche.

Low, wide and sitting on a 2920mm wheelbase to optimise high speed handling and weight distribution, the Panamera has a classic sportscar profile, yet delivers handsomely on its goal of providing a generous rear seat package with excellent head and leg room, and a good boot space.

Ingress and egress to the rear seat though not as easy as it is in, say, a 7 Series or S-Class is very good. Once in position in the low slung individual sports buckets there is ample legroom even for tall passengers sitting behind a similarly lofty driver. Scalloping of the headlining ensures better than adequate headroom and visibility, too, and there's no sense of the rear glass being too close for comfort.

there is a lack of foot space beneath the front seats and this, combined with a high sill, requires a bit of manoeuvring to get your feet in and out cleanly.

The rear seats are mounted well inboard and styled to create the sense of a second cockpit. In higher specced models rear seat passengers have access to individual climate controls, security blinds on the rear and side windows, seat heating and cooling, and individual bucket seat adjustment.

The seats are firm and quite heavily bolstered, with a prominent headrest and centre console that, for my money, creates an environment that's a bit too firm for the car's luxury positioning. But there is no doubt that you're held snugly in position, should your driver decide to show you the Panamera's wares.

Those wares are impressive, whether in one of the two atmo-V8 powered models, or in the range-topping turbo. The 4.8-litre V8 is essentially the same engine in the Cayenne SUV, but has come in for revisions aimed at reducing weight and improving responsiveness. In both the RWD Panamera S and the all-wheel-drive Panamera 4S, the engine pumps out a healthy 294kW at 6500 rpm and 500Nm from 3500 to 5000 rpm. The Turbo ups the ante substantially to 368kW at 6000rpm and 700Nm form 2250rpm 4500rpm.

Weights for the S and 4S are 1800kg and 1860kg respectively, with the Turbo the beefiest of the three at 1970kg. Of course, it's the turbo that smashes the acceleration times of its atmo stablemates, with a devastating 4.2sec 0-100km/h sprint, thundering on to 200km/h in 13.9 secs. But back down the league tables the extra grip of the 4S sees it pip the S by four-tenths, with its 5.0sec 0-100km/h sprint. And, if you'd been a traditionalist and ticked the no-cost six-speed manual option on the S, instead of the PDK, you'd have given away another two tenths to the 4S. In the 0-200km/h sprint, the PDK-equipped S and 4S are line ball at 18.5secs each.

Top speeds for the trio are 285, 282 and 303km/h respectively, which ought to be about enough for most folk.

Porsche's brilliant PDK double clutch gearbox, the same as that recently unveiled on the updated 911 and Boxster, is the standard gearbox across the range. The absence of a conventional manual altogether would be anathema to Porsche purists so the option is there - on the base model. Porsche Australia expects take-up to be "virtually zero" and no manuals were available to drive at the launch.

Much has already been written about the quality of the PDK gearbox and its application in the Panamera only builds on this glowing reputation. The automated twin clutch system is little short of brilliant, slamming home shifts with lightning speed and brutal efficiency when in full attack mode, or ambling effortlessly up through the cogs in near seamless fashion at lower speeds. Given the 'box's ability to have its shift speed altered at the touch of a button there's little real need to select the ratios yourself, although this is an option both via the stick shift or the steering wheel mounted paddles (still the wrong way 'round, we regret to report).

The system is not flawless, and there are occasions where you detect a slightly awkward up or down shift, mostly when ambling along at low speeds. But this is the exception rather than the norm.

Porsche Active Suspension management (PASM) is standard on all versions, offering a wide range of adjustment via three manually selectable damper settings that each have a distinctive character ranging from comfort to sporting. Adaptive air suspension, capable of lowering the car by 25mm and firming spring rates, is standard on the Turbo and an option on the S and 4S.

The car is impressive enough when left to its own devices, but for drivers who like to get involved with vehicle setup there are plenty of buttons to punch. These include a standard Sports button which changes engine mapping, PDK shift speed and drive distribution in AWD models. There's also a Sports Plus button if you've ticked the Sports Chrono option, which takes things up another notch again, and in the case of the Turbo activates an overboost function that bumps up torque by 10 percent. The Sports Chrono package also brings with it a launch control function which, we can confirm, works with brutal efficiency in shaving two tenths off the relevant models' 0-100km/h time.

Significantly, Porsche has avoided the trend to have vehicle set-ups buried in selectable computer menus, and all performance enhancing controls for the Panamera are arranged in an array of buttons either side of the shift selector. The idea works well and, after only a short time at the wheel I found myself comfortably flicking between the car's different suspension settings as road conditions changed.

Of course, given the Panamera's size, cost and V8 powertrains, it's likely to come into the gun sights of environmentalists pushing for reductions to fuel consumption and C02 emissions. Porsche claims to have done its bit in this regard via the introduction of PDK across the range (a saving of 0.8 litres/100km in the New European Driving Cycle), efforts to keep weight down, and the fitment of stop-start technology across the range. There are also more fuel-efficient hybrid and V6 models in the pipeline. The combined cycle figures for the S and 4S with PDK are a respectable 10.8 and 11.1L/100km, with the Turbo getting through 12.2L/100km.

The stop start tech works as seamlessly as any we've driven, turning the ignition off when the car rolls to a halt, and restarting the moment the driver's foot comes off the brake pedal. The system can be deactivated at the push of a button and will not operate if you've selected Sports Plus, or if hot weather demands constant air-conditioning effort to maintain cabin temperature. Sensors also detect if the battery has been subjected to too much cranking effort and will circumvent the stop-start system where necessary to maintain battery charge.

Pricing for the new Panamera starts at $270,200 for the S, rising to $282,400 for the 4S, and topping out at $364,900 for the Turbo. However, even after paying the better part of $400k for the Turbo, there are plenty of optional extras not included in the price. These include such features as carbon-ceramic brakes, sports exhaust, the Sports Chrono pack, 20inch wheels (18s are standard on the lower models, 19s on the Turbo), and a thunderously impressive 16-speaker, 16-amp channel Burmester audio system that'll set you back a neat $8590.

Of the 20,000 Panamera's Porsche expects to shift in the first 12-months on-sale, Australian hopes to sell around 150 to 200 of these, with sales starting in October. Estimated sales split is 50 percent Panamera S, 15 percent 4S and 35 percent Turbo.

Anyone expecting to get in the Panamera and experience a 911-like driving experience is in for a disappointment. The car simply doesn't behave like a 911, and it especially doesn't steer like one. This should come as no surprise given its weight, dimensions and front-engined layout . At 4970mm long by 2114mm wide, the Panamera is a genuinely big machine and it follows that it doesn't have the agility of its smaller sibling.

However, it is an undeniably exhilarating car and one that's capable of delivering truly impressive levels of performance, with a high degree of comfort and safety. The car steers, stops and handles like a Porsche should, and there is little about the driving experience to be overly critical of. It's fast, well built, with a beautifully finished interior, and comes loaded with impressive technology. The Panamera is a fascinating new contender in the sports luxury segment, one that quite possibly will become the new benchmark by which rivals are measured. It deserves the attention of buyers in this segment and promises to give incumbents such as the BMW M5 plenty of headaches in the years to come.