Parkers overall rating: 3 out of 5 3.0

Largely the same engines as found in the Vectra, so there’s 1.8, 2.0T, 2.2, 2.8T and 3.2 V6 petrol engines and 1.9 CDTi, 2.2 DTi, 2.0 DTi and 3.0 V6 diesels. The 2.8T's turbocharged V6 is the most potent in the line-up and saw a power increase for 2007. It doesn't quite have the clout of the Vectra VXR, but 250bhp is still plenty. Most buyers steer clear of the petrols and focus on the excellent diesels.

The 1.9 CDTi is the most popular; it’s quick – getting from 0-60mph in 10.2 seconds in 150bhp form (a 120bhp version is also available) and on to a top speed of up to 127mph. The 1.9 CDTi wasn’t launched until 2004, so buyers looking for an earlier diesel should go for the 2.2-litre. It performs similarly to the 1.9-litre, but comes in much cheaper.

The 2.0 DTi is old fashioned, noisy and best avoided unless you’re on the tightest of budgets.

Signum is at its best on the motorway, where its soft ride makes for relaxed long distance cruising. Models from mid-2005 benefit from a re-tune, designed at making Signum better to drive. The result is that the steering is sharper and the car rolls a little less, though all cars - even those with Sport suspension - err on the side of comfort.