Jaguar XJ 3.0 V6 S/C

The Jaguar edges to victory in this test on personality and style, but there’s little to separate the two cars on raw performance – both are incredibly refined at any speed. Just don’t expect the XJ’s new engine to cut the steep running costs. Our meagre test economy and a road tax bill of £270 a year will be enough to convince most buyers to opt for a diesel, so this V6 is likely to be a rare sight in the UK.

The Jaguar XJ has always been high on pomp and circumstance, but a little low on substance – so a refreshed model for 2013 has now arrived to help change all that.

When the XJ 3.0-litre diesel lost out to the Audi A8 last year, we criticised its overly firm suspension and lack of rear headroom, but praised its sporty dynamics. With a spirited new V6 petrol engine under its long bonnet, it should now have a much better chance of beating the A8.

From the outside, you’re unlikely to spot any changes from the current XJ, but with its sculpted lines and low roof it’s still the most desirable luxury saloon on the market.

Our test car came with the optional £2,445 Sport Exterior pack, which includes 20-inch Venom alloy wheels, red brake calipers, a gloss black grille and an aerodynamic front splitter. We’re still not convinced by the rear view, with its clumsy gloss-black C-pillar inserts, but the long LED light clusters and shapely boot certainly draw the eye more than the uninspiring Audi.

It’s a similar story inside, where one glance over the leather-lined dash is enough to remind you that the Jaguar is all about theatre. The starter button pulsates red before you push it, while the door sills and huge air vents are picked out in stylish Phosphor Blue lighting – this classy touch is a £1,000 option. For the most part, though, the Premium Luxury spec comes well equipped, with heated leather seats, touchscreen sat-nav and twin glass roofs all fitted as standard.

Some of the plastic buttons on the dash don’t have the same robust quality as the Audi’s, but the Jaguar looks fantastic. It’s just a pity that, although the updated infotainment system is now slightly easier to use, the screen is dominated by too much text, and it soon becomes covered in grubby fingermarks.

Niggles remain about passenger space as well. The long-wheelbase car in our pictures is roomy enough, but the standard model we tested will be tight on headroom for anyone over six foot tall. The XJ feels wider than the Audi inside, though, and light from the glass roof overcomes the gloom created by the dark suede headlining and shallow side windows.

The 520-litre boot has a powered lid and, while the opening is narrow, it’s designed to fit awkward items such as a set of golf clubs. However, the real revelation is in the way the new XJ drives. Spring and damper tweaks have smoothed the rough edges off the ride at lower speeds, so it’s now more comfortable in town, while the whisper-quiet engine is mated to a slick new eight-speed ZF auto gearbox.

Turn into a corner, and the steering is still a little too light and lacking in feel, but the Jag is agile and responsive, and the 450Nm of torque means there’s hardly any drop in performance over the old naturally aspirated V8 model. You get a hint of supercharged whine at 3,000rpm and above, and a menacing growl from the twin exhausts, but this fits well with the big Jaguar’s charismatic and sporty appeal.

Still, even with direct injection and stop-start, the V6 Jag will be just as costly to run as its predecessor – we returned a disappointing 18.1mpg on test. And this could hold it back.