Why is it that it still seems ever so slightly sacrilegious to put a diesel engine under the bonnet of something as beautiful as an Alfa Romeo 159? After all, modern diesels have come on leaps and bounds in recent years and in many respects are more desirable than their petrol counterparts. Sales figures would certainly suggest so. Nevertheless, diesel engines still have a reputation as unsubtle, weighty, oily things that should be kept locked away. A quick 'mental floss' is required before you get behind the wheel of a 159 JTD.

In total, five engines are offered from launch, split between two diesels and three petrol powerplants. The turbodiesels, priced from £20,750, are familiar fare, having seen service in other Alfa models, and are carried-over largely unchanged. That's no bad thing because they're all top-notch engines. The entry-level diesel option is the 150bhp 1.9-litre Multijet unit, while the range-topping oil-burner is the 2.4-litre 210bhp Multijet JTD. This is an absolute stormer, capable of zipping to 60mph in a tad under 8 seconds.

Both engines have something to be said for them, but the 2.4-litre unit is particularly impressive. This is one of the most advanced diesel engines you can buy anywhere and comes complete with a counterbalancing shaft to all but do away with almost every one of those traditional diesel rumbles. Common-rail technology we're well familiar with by now, but what exactly do Alfa mean by Multijet?

Here, injection pressure is independent of engine speed and can therefore be varied throughout the rev range, irrespective of the amount of diesel being delivered. This improves combustion, which has significant benefits for both performance and economy. Performance first. The rest to sixty sprint takes just over 8 seconds on the way to 140mph - but that only tells a small part of the story. The pulling power of this engine is just astonishing. This is thanks to a 284Ibft peak torque figure that's greater even than the classic 3.2-litre V6 24v engine can muster.

"The 159 JTD is a hard car to evaluate. The temptation to get a little star struck is almost overwhelming"

Mind you, it's necessary to adopt a distinctly un-Alfa-like driving style to get the most out of the JTD. Instead of searing the engine up to the red line as you would in a JTS petrol model, you have to get used to changing up a lot earlier. The surge of power begins at 1,500rpm and is all over by 4,500rpm. In-between is enough acceleration to take you comfortably into licence-confiscation territory. Of course, you don't get that lovely JTS zing while you're doing it - though the five-cylinder engine's note is much more appealing then that of a conventional diesel. But you don't buy a car like this for aural pleasure.

Alfa Romeo's clever Q-Tronic gearbox is also available as an added extra. This allows the car to be driven in automatic mode with all the functions typical of an automatic transmission (parking, reverse, neutral and drive) or in sequential mode by simply moving the gear selector.

Alfa reckon that, thanks to their Multijet technology, this 159 is on average 15% more frugal than its immediate rivals - and the figures bear this out. With an average fuel economy of around 43mpg, this is a car that doesn't penalise you for having fun.

This market sector has changed a good deal in the past few years. Whereas a compact executive car was once an exclusive vehicle with quite some cachet, the collapse of the traditional fleet market took many customers out of Mondeos and Vectras and many of them have opted for BMWs. Alfa Romeo initially took advantage of this trend with the 156 but it's a fast moving market and the company's uncertain dalliance with General Motors perhaps stalled the introduction of the 159 for long enough to dent the company's bottom line.

Still, better late than never. The 159 has grown in virtually every dimension compared to the 156, but it's still a very sharp piece of styling. Watching one appear in my rear-view at the Nurburgring, I can assure you this vehicle has more overtaking presence than almost any BMW, the gimlet-eyed headlamps and razor-sharp front grille looking rather intimidating. The rear end is genuinely tricky to differentiate from the 156 at first glance, but the side view shows sharper creasing and swage lines and a longer front end. As cohesive a piece of penmanship as the 156 was, the 159 is a better balanced car.

It's not worth pretending that the Alfa 159 can hold a candle to a BMW 3 Series as an enthusiast's performance car but in terms of raw torque, the 210bhp version is virtually as exciting as anything Munich can produce. Perhaps the 3 Series is the wrong car against which to benchmark the 159. It seems a more natural competitor to top-end Honda Accords and Saab 9-3s. This 'sub premium' compact executive sector still yields significant returns and is populated by cars like the Volvo S60 and the Jaguar X-TYPE, cars which the Alfa compares very favourably to.

The architecture of the 159's cabin is perhaps a little disappointing, offering an evolution of the 156's fascia which looked great in '98 but which now looks a little dated compared to the more imaginative designs. Build quality seems better than before and rear legroom and headroom have both improved, although you'd opt for a Saab or Volvo if this was a priority. The boot, however, is way bigger than you'd have any right to expect and the folding rear seats endow the 159 with an admirable load carrying ability.

The 159 diesel range offers a beguiling blend of elegance and practicality. You can forgive the fact that it's behind the very cream of the crop in most departments because its overall showing is so strong. At last a diesel car you can really lose your heart to.

TOP 5 159 DEALS

The results below show the top 159 deals on buyacar

	Alfa Romeo 159 1.9 JTDM 16v Lusso 4dr Saloon
	ETR	Mthly £359	Saving £2,652	Price £19,598
	Alfa Romeo 159 1.9 JTDM 16v Lusso 5dr Sportwagon Estate
	ETR	Mthly £377	Saving £2,819	Price £20,531
	Alfa Romeo 159 2.4 JTDM Lusso 5dr QTRONIC Sportwagon Estate
	ETR	Mthly £445	Saving £3,407	Price £23,893
	Alfa Romeo 159 1.9 JTDM 16v Lusso 5dr QTRONIC Sportwagon Estate
	ETR	Mthly £403	Saving £3,028	Price £21,772
	Alfa Romeo 159 1.9 JTDM 16v Lusso 4dr QTRONIC Saloon
	ETR	Mthly £385	Saving £2,862	Price £20,838

typical 10.10% APR

PCP finance quote over 48 months,  10,000 miles pa,  deposit of £1000