BMW 5 Series 550e review: bulky, ugly... and really very good

Wow, a new BMW 5 Series with an actual straight-six petrol?

Yup. We've driven this car with all-electric power. The cheapest in the range has a four-cylinder petrol. This 550 has a straight-six - woo hoo - but if we give you its full name you'll see things aren't quite that simple. This is the 550e xDrive M Sport.

Let's unpack the Scrabble. The e means it's a plug-in hybrid. The xDrive part brings the front wheels into the driving as well as the rear. The M Sport package isn't just cosmetics: it crucially adds rear-wheel steering and adaptive damping.

Those sets of powertrain and chassis technologies give you a car of multiple identities. Better yet, all those different personalities work really well.

By the way, the new 5 is available as pure-petrol, PHEV and full EV. And even as a diesel in mainland Europe. But not here. Boo – I tested the 520d xDrive and it's smooth and quick enough and super-economical.

OK, start with the 550e's power.

A 3.0-litre turbo petrol six is appetising enough. Geared into that is an electric motor. The combined power is 489bhp, enough for a 0-62mph time of 4.3 seconds.

The integration of the two power sources is superb even in hybrid mode when the engine is cutting in and put, you seldom feel any kind of jolt.

Go to sport mode and the sweet, revvy engine never stops anyway. The extra shove of the electric motor, combined with the super-attentive downshifts of the transmission, never leave you off boost. It's an almost wildly quick car.

And as a plug-in?

In electric mode, there's decent enough suburban performance at hand – the motor makes 197bhp on its own, so actually it can drive the car at motorway speed, but it takes a while to get there.

The battery is 19.4kWh. Depending on tyres, that's good for a WLTP range of around 60 miles, so with a charger at home or work that's a useful daily mileage.

It also gets it down to a CO2 figure of between 19 and 23g/km, proper company-car catnip.

And the chassis?

Well, two cars in one really. Both of them grippy and assured, but very different.

In the comfort mode (bizarrely labelled 'personal'), it's a dreamboat, wafting along with the sort of soft ride you'd expect of a big Mercedes. The steering is accurate but takes big sweeping movements. It's a marvellous thing for long relaxed drives. Plus the 4WD makes it reassuringly secure.

Swipe the display into sport mode and it all changes. The four-wheel steering effectively shortens the wheelbase, making the steering quicker and sharper-feeling. The suspension tautens, and initial roll is checked. The ESP loosens a little and in departing from a tight bend you feel the rearward torque bias. The engine sounds fruitier and the transmission is more alert. It's a driving machine connected to your senses.

It's remarkable that a series of systems under digital control can feel so natural and alive. But they do.

(By the way, among the electric i5 models, the eDrive40 doesn't have the 4WS or adaptive suspension and the M60 xDrive does. You can tell in the first mile.)

Apart from that?

Click on these words for our review of the i5 for more on the cabin and the alternative electric drivetrains.

And a verdict?

Well, the 550e xDrive has the same problems as I do: it's bulky and ugly. I just wish I was this clever and this good company.