Road Test: Citroen C6 3.0 HDi V6 Exclusive 4dr Auto

The Citroen C6 is going to cause punch-ups. Not in the rush to storm dealers' showrooms, but between your head and your heart.

Wallop! Your head says, 'stay safe, buy a BMW, Mercedes or Audi.' Kerrunch! Your heart says, 'Just look at it - the C6 is exquisite.' Pow! 'What about residual values? It'll plummet like a skydiver who's forgotten to pull the ripcord.'

Bash! 'But just look at it.'

This debate between your vital organs is slugged out doggedly with the 2.7-litre V6 turbodiesel model that is set to make up 80 per cent of the small number of C6s sold in the UK.

When it comes to three-litre V6 petrol model, your heart may well come off worst in the argument.

The petrol version has the same chic Parisian looks inside and out, and the same seductive interior that will no doubt see Jacques Chirac stepping out of a C6 presidential car sometime in the future.

Where the three-litre petrol C6 has a problem is that it's neither as quick as the diesel, nor as frugal. Fuel economy of 25.2mpg is woeful, when BMW can manage 32.1mpg from a 530i.

The Citroen takes even more of a battering when it comes to company car tax, because it sits in the top 35 per cent band, while that same BMW 5-Series is down in the 30-per-cent category.

That's a big lump of extra cash a business user will pay as benefit in kind to run a C6 instead of the safe-bet BMW.

We can live with the 3.0 V6's slightly slower 0-62mph time than that of the diesel model, but it gives more of Gallic shrug when asked to overtake. At least the standard six-speed auto 'box is smooth in both.

The question of depreciation still hangs in the air around the C6. Citroen tells us limited supply and buyers predominantly using company cash to buy one will keep used values strong, but we're already rubbing our chins.

We really want the C6 to succeed because it's something different from the ubiquitous German exec saloon, but we just can't bring ourselves to recommend a private buyer to pay for one with his or her own cash.

The C6 requires you to adjust your own settings to understand it, but whether you are prepared to or not will be a deciding factor in you paying for one or not.

It's quite tempting for the diesel, but my head wins for the petrol - more because it's not such a good drive than the landslide depreciation it faces.

Alisdair Suttie