We already knew BMW's 3.0-litre twin-turbo diesel was one of the finest engines out there and in the X5, its position in the oil-burning firmament is confirmed. 0-60mph takes 7s, there's a 146mph top speed and you still get 34mpg economy with lower emissions than a 2.2-litre Alfa Romeo 159. Combined with the X5's class-leading on-road dynamics, spacious interior and strong build quality, it makes a formidable 4x4.

Are big 4x4 vehicles getting a raw deal in the current political climate? Diving one certainly seems to be a sure-fire method of driving a wedge between yourself and other road users but are the frowns from pedestrians and looks of thinly-veiled contempt from cyclists and citycar drivers justified? BMW have a vehicle that presents a convincing case to the contrary, largely thanks to its use of one of the world's best engines. Could you learn to love an X5 3.0sd?

This isn't an exercise in defending big 4x4s. There's no doubt that these vehicles are bristling with redundant capability when they're driven exclusively on tarmac, as the majority of them tend to be. It's capability which weighs a lot and takes up a lot of valuable road space so there's definitely a question mark there in terms of efficiency. What we can also say is that large 4x4 vehicles offer definite practical advantages to their owners, and that people who write off all 4x4 vehicles as gas-guzzlers should examine the facts. Even luxury 4x4s like BMW's X5 can be rendered relatively benign environmentally by a modern diesel engine. An X5 3.0sd produces less CO2 than models like the Ford Mondeo 2.5T, the Nissan 350Z and the Alfa Romeo 2.2 JTS. You could safely drive your kids to school in any of those without being made to feel like an outcast by the world at large.

The 3.0sd engine is quite a piece of work, even by BMW's high standards. Also found in the misleadingly titled 535d and 335d, it's a 3.0-litre diesel engine that achieves its 286bhp power output with the aid of two turbochargers. The set-up avoids the 'lag and lunge' characteristics of some powerful diesel engines by employing a small turbo that spools up quickly to fire the X5 off the line and a larger one to deliver mid to top-end grunt. The result is a smooth flow of torque with the sizable peak output of 580Nm available from just 1,750rpm. The associated performance figures are eye-opening for a vehicle tipping the scales at 2,185kg. Seven seconds are all that's required for the X5 to hit 60mph from a standing start and the top speed is 146mph.

"The 3.0sd has to be the pick of the current X5 range.."

BMW built the X5 to be the best handling luxury 4x4 on the road and it's still there or thereabouts with only the Porsche Cayenne offering a serious challenge. What the X5 isn't is a capable off-road vehicle. It lacks the hardcore features, like a low-range gearbox and locking differentials, that genuine mud-pluggers rely on but BMW's decision to concentrate on tarmac performance has paid dividends during the kind of driving that most of its customers do. Tight body-control and accurate, well-weighted steering make the X5 feel almost saloon like in its responses. The vehicle's size is quickly forgotten as it flows through combinations of bends unruffled and eats-up the miles with its finely-judged suspension.

The DSC+ traction control system has been designed to give optimum purchase in slippery conditions and will allow a smidgeon of wheel spin to get you moving on snow or ice. It also includes a Hill-start assist function to prevent you rolling backwards when setting off up hill along with brake pre-tensioning, brake fade compensation and brake drying for optimum stopping performance.

The X5 resists some of the styling excesses that are on show elsewhere in the BMW line-up, going for a low key handsome look. The control interfaces inside are initially daunting with the joystick gear lever and the infamous iDrive knob on the centre console. These aren't features that will endear the X5 to potential buyers on a typical 30 minute test drive but you will get used to the iDrive or else learn to leave it alone. The benefit of having the more complex controls hidden within a labyrinthine computer menu system like the iDrive is the elegant lines of the relatively button-free fascia. It all looks superb and it doesn't feel bad either with quality materials used even where they could have gotten away with cutting some costs. The X5 never feels less than excellently assembled, its hushed cursing manner and the way the moving parts move only hinting at the depth of engineering at work.

Let's have a look at the pertinent facts. This X5 is only 19cm longer than the old model but manages to incorporate up to three rows of seats. Even with all three rows occupied, there's still 200 litres of boot space. In a more conventional five-seat configuration, the X5's boot measures 620-litres, up 155 litres on its predecessor. There's also an additional 90-litre storage compartment under the floor if you're not interested in having seven seat capacity and BMW reckons that only around 10 to 15 per cent of buyers will opt for the extra seats. This X5 is also 6cm wider than its forebear but, in another case of the engineers pulling a rabbit out of their hat, weighs no more in base specification.

The 3.0sd engine is the top choice in an X5 diesel range that accounts for 90% of total X5 sales in the UK. It commands a £42,630 price tag in standard SE form and the M-Sport package comes at a premium of over £5,000. It's a price that many customers will be willing to pay for a selection of sporty add-ons that includes 19" alloy wheels, the M bodykit, sports suspension and upgraded interior trim featuring leather sports seating. It's possible to save over £2,000 by going for the 3.0d engine that makes do with one turbocharger but the 3.0sd is far superior and well worth the premium if you can scrabble it together.

Compared to the lesser 3.0d X5, the 3.0sd model gets larger brake discs to help it cope with the extra performance. Safety equipment is reasonably generous with DSC+ fitted as standard and a full complement of airbags. It has been noted by some observers, however, that the curtain airbags do not extent to protect passengers in the optional third row of seating, an oversight that BMW really should rectify.

With combined cycle fuel consumption of 34.4mpg and 216g/km CO2 emissions, this BMW X5 is hardly the crime against the planet that some would portray it as. It's even possible to justify forking out extra for the superior performance of this 3.0sd model on the grounds that it barely uses any more fuel than the 3.0d, which achieves 34.9mpg. The 85-litre tank gives the X5 3.0sd a theoretical range close to 650 miles.

Predictably, the BMW X5 holds onto its value with some tenacity and the 3.0sd promises to be a popular choice on the used market so there's little to worry about on that score. Insurance is group 17 which is the same as the 3.0d, giving you another reason to upgrade.

BMW's six-cylinder twin-turbo diesel engine is quite a powerplant. Mated to the X5 luxury 4x4, it achieves urgent performance and fuel economy to dispel the gas-guzzler myth that certain groups seek to blanket the entire 4x4 sector with. The X5 doesn't have the off-road pedigree of its key rivals but they can't match the BMW on the tarmac. When you look at how luxury 4x4 owners actually use their vehicles, it's hard to argue with BMW's road-biased approach.

The 3.0sd has to be the pick of the current X5 range. In a money-no-object decision, you might just about plump for the V8 petrol unit but in the real world, the associated running costs and environmental guilt would prove too much of a burden for most to bear. Great performance, fuel economy that's only fractionally inferior to the 3.0d and the knowledge that you're in the company of one of the world's finest engines make give the X5 3.0sd tough to resist. What's more, you're also getting a spacious, practical and beautifully built family car. Who said the days of the 4x4 were numbered?

TOP 4 X5 DEALS

The results below show the top X5 deals on buyacar

	BMW X5 3.0d M Sport 5dr Auto Off Road
	ETR	Mthly	Saving	Price £46,486
	BMW X5 3.0d SE 5dr Auto Off Road
	ETR	Mthly	Saving	Price £41,418
	BMW X5 3.0sd M Sport 5dr Auto Off Road
	ETR	Mthly	Saving	Price £48,668
	BMW X5 3.0sd SE 5dr Auto Off Road
	ETR	Mthly	Saving	Price £43,600