Price: £29,500 approx. On sale April
Engine: 2,720cc, V6 cylinders, 24 valves, twin-turbo diesel 208bhp at 4,000rpm, 325lb ft at 1,900rpm
Transmission: Six-speed gearbox, front-wheel drive Performance: Top speed 143mph, 0-60 in 8.7sec, 32.5mpg
Not so long ago, Citroën went through a stage of denying its past. No-one could understand why the then Peugeot-Citroën chairman, Jacques Calvet, wanted to forget DSs, Traction Avants and Deux Chevaux and make Citroën into a value brand with no obvious USP, but he did. All that style, innovation, iconography. Binned.
Now look at the press brochure for the new C6. "It is a car inspired by great Citroëns of the past - the DS, CX and SM - whose design and innovative technologies have helped the marque to establish a strong heritage in large cars," it proclaims. Not the snappiest wording, but the point is made even if the XM suffers an Orwellian omission in this view of history.
It's the perfect time to launch the C6, actually, because it's half a century on from the launch of that space-age DS with its streamlined form and jet-exhaust, roof-mounted rear indicators and the oleopneumatic suspension that has smoothed the ride of every big Citroën since. If some of the DS's kudos rubs off on the C6, then Citroën may well chip away at the German-badged domination of prestige cars.
The more you look at the C6, the cleverer it seems. The low, sloping bonnet with its central ridge has a touch of the DS, true, and the concave rear window and triple side windows are reminscent of the CX, but the C6 is its own car with its own rounded-wheelarch shape and its own wrapover headlights and tail-lights.
We first saw its shape at the March 1999 Geneva show when Citroën revealed the C6 Lignage concept car. And, here it is at last, surprisingly similar to the concept but productionised with more lights, side pillars raked back less radically, a single lower-body chrome strake instead of a double, and bumper cutlines that can't be avoided.
It's a foggy day when I see the C6 in the open air for the first time. This C6 is black (the Lignage was silver), which emphasises the chrome detailing - wide front bars kinked up into double chevrons in the centre, slats below, a minimalist outline around the frameless side windows - and the convex, waistline adds to the feel of a wheeled creature emerging from the car park of Hades.
But will it be as other-worldly inside? Here, Citroën lost its nerve a bit. I was hoping for a DS-like single-spoke steering wheel, or a stationery switch-cluster in the wheel's centre like the smaller C4's, but no. What we get is a near-symmetrical dashboard with Volkswagen-like venetian-blind vents, a big central Sat Nav display and a smaller one ahead of the driver with a digital speedometer.
And then, yes! Some Citroënisation! There's a head-up display which repeats the digi-speedo, focused on a virtual point far enough ahead to be read with the road, and vital Sat Nav direction arrows can be displayed alongside the digits. This will be very useful when, later on, I'm lost in the Paris rush-hour. And then there are those door bins. These affirm the existence of original Citroënesque thought, because each door has one of these drop-down, glossy-wood-veneered semicircles big enough to swallow meaningful clutter. Their damped movements aren't perfect, but full marks for trying.
Other technobites include an electric parking brake and a device which vibrates the left or right side of the driver's seat if you wander over road lines without indicating. There is no sign of keyless starting, thankfully. With a key, you know where you are.
Like the imminent Jaguar XK, the C6 meets new pedestrian-impact legislation by popping the back of the bonnet up the instant the C6 senses impact by means of touching contacts in the soft-front bumper. This creates space between the bonnet and the hard engine beneath, so reducing the potential for injury.
So off we waft, because wafting is what a big, plush Citroën should be about. The engine - we've started with the 3.0-litre, 215bhp petrol V6, mated to the six-speed automatic transmission of all C6s - is deliciously smooth and quiet, helped by 'active' engine mountings which oscillate in concert with the engine to cancel vibrations. The side windows are laminated, which absorbs more sound, and the moving experience is serene even when giving the engine its cultured head.
Except for one thing. A Citroën on a modern version of the DS's oleopneumatic suspension - which nowadays doesn't sink when the engine is off - should still be ultra-supple over imperfect roads. In reality it's good, but not the paragon I'd hoped. There's some fidgeting underfoot, as if even Citroën's magic suspension can't quite cope with the challenges posed by the handsome but inappropriate 45-profile tyres with their shallow sidewalls. Yet the steering remains a bit vague and other-worldly, giving you only the less desirable part of the expected floating sensation.
So I press the Sport button and get beamed back to Planet Earth. Sport relieves the suspension of having to make so many calculations, because it starts from a firmer base. The ride is barely any more fidgety, and given the improvement in steering response the ride comfort now seems entirely acceptable.
The gearbox shifts smoothly and keenly. Even the brakes work progressively; the violent snatch of the old DS's brakes was something Citroën did well not to emulate in the C6, although the engineers managed it in my C4.
And now, in Paris, near the journey's end, I try the other engine: the 2.7-litre V6 turbodiesel built as a joint venture with Ford/ Jaguar/Land Rover. Citroën says 80 per cent of C6s will be so powered and it was made for this engine; it's great in all the other cars to which it has been fitted, and it's great in the C6.
What, then, are we to make of the C6? It seems very pricey for a car based on a stretched Peugeot 407 platform, even if you can have electrically reclining rear seats and you're swathed in luxury. But then it is made on a separate luxury-car line (along with the 407 Coupé), there won't be many of them (to keep it exclusive) and it's excitingly different from the prestige cars everyone else buys. You'd be brave to buy a C6, but you'd be glad if you did.
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We're getting used now to the fierce-looking new Audi front-end, and this A6 from them is a good-looking, beautifully-finished car with a great engine and the welcome bonus of four-wheel drive.
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