If the Saab 9-5 has received a slightly cool reception in this country, Saab diesels have fared even worse. Time for a change. First to the styling, which now looks more 'cutting edge', then to the diesel offering. This is now the 150bhp 1.9-litre TiD engine borrowed from the smaller 9-3 Range, an engine, Saab hope, that will give BMW sleepless nights.

This unit must single-handedly replace both diesels used in the previous 9-5 line-up, Saab-sourced 2.2 and 3.0-litre TiD units. Since the old 3.0-litre developed 176bhp, that's a tough ask. Still, prices, which start at £21,905, are keen and the performance figures, on paper at least, look very competitive.

The Saab's engine is a good example of its type and though in absolute power terms, it's some way short of the BMW 525d's creamy 177bhp 2.5-litre unit, it's also up to £7,000 cheaper. Plus the 9-5 estate (priced in this form from £22,505) compares favourably with the Touring versions of the 5 Series. Would you buy one over the BMW? Well how open-minded are you? If you've ever queued at the returns desk at IKEA, you may not be one of a growing band of far from gruntled Swedophobes. The design shortcomings of the not-obviously-chipboard Knackig coffee table may well have holed the 9-5s prospects below the waterline.

Seriously, the 1.9 TiD engine we're looking at here is a very good one indeed. Developed in conjunction with Fiat and produced at the FMA plant in Italy, Saab have a quality powerplant they could never have produced under their own steam. Mated to a six-speed manual gearbox as standard with the option of a six-speed auto, there's plenty of scope for plugging the car straight into the meat of the torque curve. With at least 90% of peak torque available in a broad load running from 1,750 to 3,250rpm, you'll be guaranteed respectable progress. After all, peak torque for the 16v engine is 315Nm so you'll not be lacking overtaking response.

"The 1.9 TiD engine we're looking at here is a very good one indeed - but will it be enough?"

The 9-5 line-up has been much improved in recent times, notably with that new front end. The chrome headlight surrounds and clean finish to the grille and bumper sections give the 9-5 serious presence without resorting to the sorts of me-too contrivances that have afflicted certain rivals. The facelift goes a whole lot further than a mere window dressing, however, and Saab claim that every piece of panelling ahead of the windscreen pillars is new. The rear end has been tidied and modernised with a more streamlined-looking rear valance and bumper assembly.

Drop inside and you'll be able to tell it's a Saab even if you're wearing a blindfold. The cliff-like fascia, the odd combination of super-soft thermoplastics and harder materials more akin to a mainstream car and the key slot on the transmission tunnel mark the 9-5 down as a product that could only have come from Trollhattan. The rather unusual steering wheel design debuted in the 9-3, not the Flash Gordon movies as some may suspect, and is actually rather more pleasant to use than its looks would suggest. There are also a number of small detail changes to the instruments and cabin. Chrome-ringed dials, an uprated information system, better quality ventilation controls and the repositioning of some minor functions to help ergonomics are all welcome, but expect a cutting edge executive car interior and you're likely to be disappointed. Swedish functionality wins out over design flair in this instance.

Various trim levels are available: Linear, Linear Sport, Vector and Vector Sport. Aside from the most astonishing cup-holder in the automotive world, there are the typical Saab design cues including the centrally mounted ignition barrel and vertiginous fascia. It's neither slick nor pretty but it feels rock solid and incredibly well thought through. In terms of cabin space, you'll find a decent amount of elbow room and (in the estate) a decent 416-litre boot which grows to 890 litres with the rear seats folded. In the saloon, there's 15.9 cu/ft of luggage capacity accessible via split-folding rear seats that also feature a ski-flap. Safety as ever, has also been a priority and all the obvious protection is there, with careful touches that even stretch to anti-whiplash head restraints and those pre-tensioning seat belts.

It's under the skin that most of the benefits will be felt. The 9-5's chassis is, much as Saab won't thank us for noting, still based on an extended Vauxhall Vectra platform, itself not the first place you'd start to build a credible executive express. Over the years Saab have fettled this pig's ear into something that may not feel like a silk purse but comes laudably close. Whereas the old model felt quite skittery when you applied the power to the front wheels mid-corner, the latest 9-5 deploys its power far more cleanly, making it feel more of a driver's tool than the old motorway mogul ever was. Nevertheless, corner it hard and Saab's reputation for safety intervenes with the improved ABS and ESP skid control combining to quickly put a lid on any slip sliding away.

Many would argue that it cuts in somewhat prematurely and they'd have a fair point, although the more lenient system employed by BMW highlights the difference in driver appeal between the two marques. With weight taken out of the subframe and more rigidity built in, the Saab feels lighter on its feet than of old, and the chassis engineers have also had a fiddle with the damper, springs and roll bar settings. The result is a far sportier drive than whilst still retaining a degree of suppleness. Body roll is now well controlled although the revised steering system is still a couple of notches from the top of the totem pole.

It's one thing to be dubbed 'best of the rest', something the 9-5 manages quite easily, but what about denting the sales of the German mainstream rivals from Mercedes, BMW and Audi? Good though the 9-5 1.9 TiD is, it's not markedly better than Teutonic rivals in any key area. When a car as good as this can't break buyer's prejudices, it's difficult to imagine what Saab have to do. Possibly give up and build something else. Planes. Now there's a market ripe for the taking.