No completely redesigned BMW is without plenty of new technology so the new 5 series – now on sale in Europe and reaching the key UK right-hand-drive market in September – features a body combining both steel and aluminium, as well as an all-aluminium chassis and suspension, writes just-auto deputy editor Graeme Roberts.

Engineers claim an industry first for the aluminium firewall, front guards and other nose panelling bonded to the steel ‘A-pillar aft’ structure. The all-aluminium ‘chassis’ has a number of enhancements including wider front and rear tracks and a longer wheelbase. The result is definitely improved driving dynamics along with claimed better fuel consumption and near perfect 50:50 axle load distribution – the 520i SE is said to achieve ‘perfect’ 50:50 balance. Significant weight reduction also provides outstanding suspension and damping comfort and, overall, the new 5 is the most refined and stable BMW we’ve driven.

High performance brakes with aluminium swing-callipers are now standard and the rack and pinion steering, with lightweight hydraulic rack offers optional ‘world first’ Active Steering or Servotronic assistance.

Active Steering (an £810 option in the UK) is simply brilliant and perhaps a portend of the “drive by wire” technology to come. This clever system offers drivers extra steering assistance at low speed as an electric motor increases or decreases the steering ratio, which varies the degree of driver input at the steering wheel. At low speeds just three quarters of a turn on the steering wheel moves the front wheels from centre-to-full lock, eliminating the need to cross hands or shuffle the wheel during low-speed parking manoeuvres, or when driving around town. It worked a treat in the tight confines of a hotel car park in the German spa town of Baden-Baden during a press drive programme yet felt completely normal, if perhaps a fraction light, at country speeds.

However, the best bit of the 5-series driving experience, we think, is Dynamic Drive, a suspension control system that minimises body sway (roll) in bends.

This £1,550 optional system uses active anti-roll bars to offset body roll in bends, significantly improving ride quality and passenger comfort. When cornering hard, the car can absorb a massive 80% of body sway at lateral forces of up to 0.6 g. But while noticeable when cornering, Dynamic Drive has no perceptible effect on the car’s road manners.

The system comprises two active anti-roll bars, a valve block with integrated sensors, a dual oil pump, yaw rate and lateral acceleration sensors and control unit.

The difference between an active anti-roll bar and a normal anti-roll bar is that a normal bar is a solid rod of metal. An active anti-roll bar is made up of a hydraulically operated swivel motor incorporating a swivel motor shaft connected to one half of each bar. The active anti-roll bars convert hydraulic pressure generated when cornering into torsional strength. When driving straight ahead, the two halves move freely, absorbing road bumps or unevenness.

A further benefit of Dynamic Drive is that it provides the best of both worlds. It provides softer suspension for added comfort during normal motorway driving but as soon as a lateral cornering force is detected body roll is reduced. This provides added comfort for passengers who are not thrown around when the car is driven enthusiastically.

PR puffery? No. We found ourselves deliberately hurling a Dynamic Drive-equipped test car harder and harder into a series of tight corners during a drive through part of the Black Forest – keeping the body flat makes the car far more controllable without tossing occupants around. The option can be specified with either Servotronic power steering (£160) or Active Steering for now but will be offered as a separate option later.

Standard cars also handle well but their cornering limits are lower and the greater body roll means hard cornering is a little uncomfortable, especially for passengers. Drive a standard car hard after a Dynamic Drive one and disappointment is sure to be felt, even though the standard chassis is actually very good.

Given the flak that greeted the first edition which debuted with 2001’s new 7-series, BMW is understandably a little defensive of its second-generation iDrive controller which arrives in the new 5 series. There’s a new Menu button – instantly returning you to the equivalent of a website’s home page – and the system has been otherwise improved, with colour coded options and four ‘access zones’ instead of the original’s eight. All functions are accessed through a series of straightforward, slide, turn and push actions with the controller. We’ve had just three days’ playing with the 7-series’ mostly confusing system and found the 5-series’ version far more intuitive though we were into day two of driving before we discovered how to mute the satellite navigation’s voice instructions.

As an aside, many previously dealer-set functions – all doors or just the driver’s door open on a first push of the remote key fob, for instance – can now be preset by the owner using the latest iDrive.

Optional head-up display (£810) arrives in the UK in April 2004, projecting information onto the windscreen via a series of mirrors. The display will give the visual illusion the information is actually displayed about two metres ahead of the car, thus requiring less driver eye re-focusing. As well as navigation directions, speed and cruise control display, the system includes Check Control messages such as ‘door open’.

Adaptive Headlights (£270) swivel by up to 15 degrees, shining light in the direction the steering is directing the car rather than where the car is pointing.

The new 5 Series offers a total of four different seating options, including Comfort Seat (£1,315), a fully electric seat with passenger memory, lumbar support for driver and passenger and back width adjustment. The comfort seat also comes with an active headrest which moves forward in the event of an impact, minimising the effect of whiplash and helping to prevent spinal injury. Even the standard seats have some electric adjustment and we loved the heated and cooled pair of chairs in a 530d that gently massaged one’s buttocks occasionally as one swiftly progressed through the countryside.

Passive safety throughout the 5 Series is co-ordinated by BMW’s Active Safety Electronics (ASE) system which features a central safety module, linked to satellite sensors located around the vehicle. In the event of an impact ASE deploys the most appropriate airbag (of the six standard bags), but also deactivates the electric fuel pump and alternator and battery, and activates the hazard-warning lights if necessary.

The controversial issue with any new BMW of late – styling – we have left to last. It sneaks into a review of the car’s technology, mostly because some of the shut lines on horizontal surfaces -around the bonnet – are quite conspicuous and must have presented a challenge to achieve with the uniform consistency of tightness and alignment seen on the sample cars.

Suffice to say the new 5 is way different from its conservative predecessor but is less controversial now we are used to the larger 7-series saloon and Z4 roadster, with which the new 5 shares some family characteristics while adopting a look all of its own. The cabin is equally dramatically styled but as well laid out for a driver as you expect of a BMW, and has not suffered from any drop in materials quality or finish, unlike a rival or two. We’d suggest reserving judgement till you see the newcomer in the metal and, perhaps like us, you’ll agree it’s colour sensitive both inside and out.

While the looks may take a while to grow on those who can actually afford a new 5, we’ll stick our necks out and say this: with all this new technology – especially Dynamic Drive – it’s the best BMW saloon yet, which is saying something.