Parkers overall rating: 3.5 out of 5 3.5

Two V6 engines are available at the top of the engine line-up, both of them offered with a six-speed automatic transmission. The 3.0-litre petrol engine offers 212bhp and sprints from 0-62mph in a moderately brisk 9.4 seconds but it's thirsty with an average fuel consumption of just 25mpg. The 2.7-litre V6 diesel has 205bhp and much more pulling power than the petrol, helping it to cover the 0-62mph sprint in 8.9 seconds.

It's a much more relaxed car to drive than the petrol, especially when it comes to overtaking. The other engine is a 2.2HDi with 173bhp. This is the only model available with a manual gearbox, but the six-speed transmission lacks feel and precision, however economy is good at 43mpg. The six-speed auto in the more powerful engines does a great job of smoothing gearshifts, but the relaxed manner in which you drive the C6 sometimes makes it difficult to provoke it to kickdown and it can be hesitant to select a gear.

In 2009 a 3.0 HDi was introduced and the V6 unit delivers an impressive 240bhp and plenty of in-gear pulling power. It offers the same 0-62mph time as the 2.7 HDi but us actually more econimical with an average fuel economy figure of 38mpg (compared to 33mpg). CO2 Emissions are also lower at 195g/km, meaning lower road tax rates.

Set up for comfort rather than responsiveness, the C6 has a complex active suspension system designed to prevent vibrations from the road reaching the occupants. Instead of conventional metal springs it uses an electronically controlled hydraulic suspension system, with two stiffness level and 16 damper settings. While the system is set up for comfort, it automatically firms up when the driver uses harsher acceleration and braking.

The steering is generally light and easy to use, but lacks feel, which combined with a wallowy nature in corners, means the C6 is not a particularly enjoyable car to drive on twisting roads. The brakes are disappointing too and the car pitches and dives a considerable amount. It's much happier wafting along the motorway than tackling bends.