Four years after its launch, BMW's 7 Series still challenges the eye. It's not an easy car to love, its complex series of sweeps, planes and unconventional proportions still appearing as befuddling as ever. Recognising that controversial rarely results in big sales, BMW toned the styling of the 3 Series back in the quest for mass market appeal but have retained the unorthodox look and feel of their luxury flagship.

It'll take a keen eye to spot the latest exterior changes. They conform to the usual checklist of targets for mid-life facelifts, with the front grille and bumper being subtly altered as well as the headlamps. BMW claim that the enhancement of the bonnet's power dome gives the car a more powerful face, and the more boldly contoured bonnet does look a good deal more like the 5 Series, which can only be good. Previously, the front of the 7 was a rather character-free zone, the broad, low mouth resembling a filter feeding shark. The back of the car has also been changed. The tacked-on boot remains although its visual effect has been lessened by a series of incremental changes that give the impression of narrowing the car. Modified tail lamps and bumper assembly are the main changes but there's also a chrome detail strip running the width of the bootlid. At the sides, there are more pronounced side sills to give the car a more contoured and planted look. Four new paint schemes have been added to the palette and the 18 and 19-inch alloy wheels have been redesigned.

The interior has been left largely alone, but the news that many prospective purchasers have been waiting for is that the infuriating iDrive system has been pared back to the simpler and slightly more intuitive version as seen on the 5 Series. Standard trim has been beefed up with all cars now featuring xenon headlamps, a headlamp cleaning system and Brake Force Display, BMW's twin stage brake lighting system that alerts following drivers as to how hard the brake pedal is being depressed. All cars specified with satellite navigation and a telephone also benefit from BMW Assist, which allows the emergency services to accurately pinpoint the location of your car.

"It's impossible to argue with the excellent sales figures the 7 Series has generated"

There are big changes on the engine front. The 730d - the model which has accounted for considerably more than half of all UK sales since its introduction - has had its powerplant thoroughly overhauled. An all aluminium cylinder block slashes weight while third generation common rail technology increases power by 12 per cent to 228bhp. Torque rises by 4 per cent to 520Nm. Its petrol-powered counterpart, the 730i, now gets the featherlight magnesium aluminium composite engine seen in the 630i and 330i. Capable of generating a hefty 258bhp, the 730i now offers the best power to weight ratio and highest output per litre of any car in its class. This power boost hasn't come at the expense of fuel economy either, the 28mpg average consumption representing a worthwhile 4.7 per cent improvement over the old 730i.

The 735i bites the bullet and is replaced by the 740i, a 4,000cc V8 engine now developing 302bhp and 390Nm of torque. With a marginal improvement in fuel economy, customers are effectively getting a 13 per cent increase in power for nothing. Sounds good to us. The world's best selling 7 Series model has long been the 745i, but with a typically Bavarian lack of sentimentality, BMW have rewarded this success with the chop. In its place is revived an old favourite badge, the 750i. Powered by a 4.8-litre V8, this Seven can heft 362bhp and accelerate to 60mph in 5.7 seconds. Despite the enormous power hike, 24.8mpg is still an everyday possibility. The top of the 7 Series tree continues to be the leviathan 760i, with its 5972cc V12 motor delivering a more than adequate 445bhp. All of the engines are also offered in the long-wheelbase bodystyle.

Apart from the engine upgrades there are also some fundamental changes under the car's skin. In order to cope with the additional power on tap, there have been wide-reaching enhancements to the 7 Series chassis. A 14mm wider track promises improved lateral stability and the all aluminium suspension has also been updated. Customers can also specify two separate suspension choices depending on their ride comfort preference. Those looking for a more dynamic steer can opt for the Sport model. The Adaptive Drive feature combines BMW's Dynamic Drive active anti roll bar and Electronic Damper Control (EDC). This quells body roll during hard cornering, converting roll energy into hydraulic pressure to deliver uncannily composed cornering for such a huge car. EDC offers the driver three ride settings - Comfort, Normal and Sport.

Although many commentators have enjoyed sniping at the fourth generation BMW 7 Series, it's impossible to argue with the sales figures. Almost 160,000 cars have found owners worldwide, making this the most successful BMW luxury car to date. It's now even better. Rivals now have something serious to chew over.

TOP 5 7 SERIES DEALS

The results below show the top 7 SERIES deals on buyacar

	BMW 7 Series 740i 4dr Auto (Pre-model) Saloon
	ETR	Mthly £1,253	Saving £6,830	Price £51,065
	BMW 7 Series 730Ld SE 4dr Auto (Pre-model) Saloon
	ETR	Mthly £1,153	Saving £6,424	Price £48,131
	BMW 7 Series 760Li 4dr Auto (Pre-model) Saloon
	ETR	Mthly £1,854	Saving £10,395	Price £75,150
	BMW 7 Series 730Ld SE Carbon Exclusive Edition 4dr Auto Spec edn Saloon
	ETR	Mthly	Saving £7,128	Price £52,887
	BMW 7 Series 730d SE Stratus Exclusive Edition 4dr Auto Spec edn Saloon
	ETR	Mthly	Saving £6,717	Price £50,108

typical 11.90% APR

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