Road Test: BMW 730D SE

Model: BMW 730d SE
Price: £49,650, on sale now
Engine: 2,990cc, six cylinders, 24 valves, turbodiesel, 231bhp at 4,000rpm, 384lb ft at 2,000-2,750rpm
Transmission: six-speed automatic gearbox, rear-wheel drive
Performance: 149mph, 0 to 60mph in 7.6 seconds, 34.5mpg official average
CO2: 216g/km

They all look a little strange, these latest BMWs. Odd enough for you never to be quite sure if what appears in your rear-view mirror is a 3-series, a 5-series or a 7-series. Get the image in context, though, and you can see that with ascending size go both ascending age and ascending strangeness.

The current-generation 7-series, born in 2001, was considered so odd that the critics thought that BMW had succumbed to corporate insanity. The design director Chris Bangle was vilified for his ruination of the former BMW theme of discreet, neat, acceptable assertiveness; the 7-series was pilloried for its conflict of lines and the way the boot-lid seemed to be perched on top of the tail as though borrowed from another car.

And then there was iDrive. Not only iDrive, but an electric parking brake and a steering-column-mounted automatic transmission selector that, like the wiper and indicator stalks, always sprung back to the middle position so that you never had a tactile memory of where you were. I remember receiving a 10-minute lecture on the advantages of iDrive (one big knob to control all sorts of things via menus, a screen and multiple turns, presses and prods), just before setting off on my first 7-series drive. After that, could I get the BMW to go? I could not. Every subliminal thing that I'd learnt in nearly three decades of driving had to be forgotten, my mind wiped to Year Zero. How would a set-in-his-ways company big shot, eyeing up the 7-series for possible purchase, cope with this? Would a computer-savvy teenager become the most popular 7-series option?

And yet, the shock subsided, diluted with the arrival of more Bangle-influenced BMWs, and one day (I wasn't driving to Damascus), I saw a black 7-series and was suddenly struck, hard, by how menacingly cool it looked. Brooding, frowning face, slashed lines and knife-cut edges, nothing soft or apologetic at all. Strangest of the new breed it still was, but also the most dramatic and pure. Compared with the retro-fixation of big Jaguars, the visual politeness of Audis and Mercedes-Benzes, and the utter blandness of the previous-generation Seven, the 2001 version was a revelation belatedly appreciated.

But BMW realised that it had overstepped the mark. The 7-series was still too daring for its intended clientele, so BMW regroomed it for polite society. You see the result here: same basic shape, but smoother and rounder at the front, tidier at the tail, still dramatic but no longer unsettling. It's a more credible look that still has a big presence.

With the new look come some revised engines. Most of the petrol ones have efficiency-enhancing Valvetronic valve control (it uses variable valve lift in place of energy-sapping throttles), but the range-topping, 445bhp V12 is unchanged. Most popular, though, will be the diesel 730d tested here. This 3.0-litre, straight-six engine delivers 231bhp and an epic 384lb ft of torque, all with an official fuel consumption of 34.5mpg. Unlike the previous 730d, this one has a lightweight aluminium block and piezo-crystal injectors, the crystals' tiny but instant and ultra-accurate movements offering tightly controlled fuelling.

Inside, the iDrive is claimed to be easier to use and has a leather insert in its giant control knob. And if you pay an extra £2,450 for the Rear Entertainment Package, you get not one but two iDrives. Back-seat drivers can have the time of their lives, hijacking all sorts of functions.

It was in just such a 730d that family Simister has just returned from a thorough test to the South of France and back. Two iDrives and two teenage girls in the spacious rear cabin to act as an adult/iDrive interface. It was marvellous. They got the navigation to work with just a wiggle and a prod, they knew more about the 730d's range, fuel consumption and functions than I did, and, loading CDs and DVDs into all kinds of slots (DVDs in the boot, CDs in the dashboard), they plugged in their headphones and watched DVDs on their very own screen between the front seats.

And what did I think of the 730d? It felt massive at first, even though it was the regular-length version and not the long-wheelbase model, but with quick, accurate steering and quite taut suspension, it soon seemed to shrink. Manoeuvring in tight spaces soon made it grow again, but the world's best parking-sensor system proved a godsend. It works for both front and rear, and the beeps accompany an aerial view of the 730d on the main screen, which shows, in different colours according to proximity, where the obstacles are. A flood of red follows anyone walking around the extremities.

That taut ride, though never uncomfortable, is a key difference between the 730d and the Jaguar XJ6 TDVi recently tested. Another is the sound of the engine. The Jaguar is almost unbelievably quiet and hard to identify aurally as a diesel, while the BMW can be quite vocal. Yet it, too, doesn't sound at all diesel-like from inside and does so only at idle from the outside. Rather, it has the sort of deep, resonant note of a sporting six-cylinder petrol engine from the 1950s or 1960s. It's possibly the most aurally characterful diesel made today.

And it's matched to an excellent six-speed automatic transmission from ZF, whose gearshifts both up and down are almost always jerk-free. There's a Sport mode to sharpen its reflexes, useful on winding mountain roads, and a manual mode which, used intelligently, guarantees a perfectly smooth and swift shift every time, activated by buttons on the steering-wheel.

I liked this semi-limo that handles with such unlikely precision. More than the excellent Jaguar? It looks cooler and has more toys, but it's significantly more expensive and not quite such an engaging drive. The BMW 7-series has come in from the cold, no doubt about that, but for me the Jaguar still rules the class.

The rivals

AUDI A8 3.0 TDi QUATTRO SE, £48,365

Four-wheel drive is a benefit in poor weather, and the A8 has a weight advantage thanks to aluminium construction. Looks ultra-modern, is beautifully built, but is neither as relaxed nor as fun to drive as the BMW.

JAGUAR XJ6 TDV6, £43,995

Cheapest in the class is also marginally the most economical, thanks to Audi-like aluminium construction, and the quietest. It also rides and handles the best, and recent XJ revisions have made it look less retro. Sport spec is best.

MERCEDES-BENZ S320 CDI, £50,965

Up to now this has been the best luxury-car all-rounder of all, and it still looks classically beautiful. Across Europe it's the best seller in the class, so it will be interesting to see how the imminent new one fares. It's not handsome.