We’ve been driving the 640d Coupé in M Sport trim. Its power delivery off the line is deliciously smooth, making it a docile thing to drive around town in comparison with the more urgent 650i we tried earlier in the year.
It’s no slouch out on the open road, though. Power stays at 309bhp, which is enough to launch you from zero to 62mph in a punchy 5.3secs. However, all that torque – 465lb ft to be precise – being available from just 1500rpm, makes it feel almost as fast as the more powerful V8 in the gears. Apart from a little low-end diesel clatter, it sounds great too, with a meaty straight-six growl at full chat.
The 3.0-litre twin-turbo diesel engine is now Euro 6 compliant and more efficient. Unbelievably, considering the performance potential and weight of the 6, this engine should deliver up to 52.3 mpg (with 18in wheels) according to BMW, which gives a potential touring range of a staggering 786 miles.
The eight-speed auto gearbox works beautifully. Up-changes are slick and thanks to its GPS-based awareness of the surroundings, it will select and hold on to the right gear (mostly) for any given bend or long downhill stretch. As a result, you tend to ignore the steering wheel-mounted paddles.
BMW claims to have fettled the electric steering’s mapping and the suspension’s damper settings, in a bid to sharpen the handling whilst taking out some harshness from the 6’s ride - it’s not been a complete success. The steering still doesn’t feel very linear, being either too light dead-centre or too heavy as you pile on lock, depending on which mode you select.
It’s also very camber sensitive. You can be holding onto the steering wheel mid-bend, feeling it load up in your palm, only for the weight to suddenly vanish, then reappear again, making it darn tricky to hold your chosen line.
Our M Sport test car was fitted with stiffer suspension and 20in wheels as standard. If you set the suspension to Comfort mode this will take the sting out of general surface imperfections, but here in the UK we have more specialist road surfaces too, mainly ranging from bad to appalling.
Even in Comfort, over such surfaces the 6 starts to crash and thump in a way that doesn’t suit its grand touring character. Stiffen it up further in Sport or Sport Plus and it starts to become really cruel unless the road ahead is dead smooth.
Being such a big car, the 6 has never felt overly wieldy. That said, you can hustle it along a B-road, where it displays decent body control and a playful rear-end when the mood takes you. The brakes shed speed quickly when required to as well.
If you were to do a 6 Series pros and cons list, cabin ambience would definitely be on the former. The new leatherwork and high-gloss centre console elevate what was already a top-notch interior; the comfortable multi-adjustable seats, fabulous driving position, generous space up front and BMW’s unbeatable iDrive infotainment system seal the deal.