Parkers overall rating: 4 out of 5 4.0

BMW M6 Gran Coupe performance is really rather epic.

Power comes from the same engine as the M5 Saloon and M6 Coupe – a 4.4-litre, twin-turbocharged petrol V8 with 552bhp. That’s an impressive enough figure but it’s the powerplant’s 680Nm of torque (available from just 1,500rpm all the way to 5,750rpm) that gives it its brutal acceleration.

The Gran Coupe will get from 0-62mph in 4.2 seconds but in-gear acceleration at higher speeds is impressive too. That V8 likes to rev too – peak power is spread evenly between 6,000 and 7,000rpm, with the limiter kicking in at 7,200rpm – but it’s also very flexible.

Third gear alone is capable of taking the car from a crawl to licence-worrying speeds in short order, and if there’s any criticism to be levelled at this car it’s that the performance is so ferocious that any bouts of acceleration within UK speed limits are over almost as soon as they’ve begun. Clearly it’s a car far better suited to the German autobahns or fast-paced race circuits.

All M6 Gran Coupes use BMW’s impressive seven-speed dual-clutch transmission (DCT) which as its name suggests uses two clutches for very fast and smooth shifts.

You can actually choose how fast you would like the gear changes to be, with three levels of shift speed. In the fastest setting the gears change with a rather abrupt thump, but in the other two they are silky smooth. There are also three engine map settings to choose from for a more responsive or a more economical setup.

The M6 Gran Coupe we tested was fitted with the optional Competition package, which boosts power by an extra 15bhp and trims a tenth of a second from the 0-62mph time. As well as the extra power it also includes some altered chassis settings – more on which in the Handling section below.

Our test took place on UK roads in the winter and the M6 struggled to put its huge power down on cold and damp surfaces, with the traction control system working overtime to keep wheelspin in check even when driving very gently. This is a car that needs to be driven with a degree of restraint.

Top speed is electronically limited to 155mph although it’s possible to have the limiter increased at extra cost.

At more than five metres long, the M6 Gran Coupe is a big car but it does a great job of shrinking around you when you gather speed. There’s no getting away from the fact that it’s a heavy car but it’s very agile for a machine that weighs 1,875kg.

It does sit on enormously wide tyres but the equally enormous power and torque mean it can break traction very easily. The standard stability control system does a good job of keeping everything in check, however, and also features a halfway-house setting that allows a fair amount of slip before stepping in to keep affairs in order.

A long wheelbase of nearly three metres means the M6 Gran Coupe behaves predictably when you do overstep the mark.

As with the engine and gearbox, there are three configurable modes for the adaptive dampers and power steering as standard. In the softest ‘Comfort’ setting the suspension deals with large bumps fairly well while in its firmest setting the car feels taut and planted on smooth roads.

The three power steering weight settings, which increase the amount of effort needed to turn the wheel, are less useful – the heaviest of the three is truck-like in its weighting and only serves to make the car feel cumbersome.

Our test car was fitted with the optional Competition package, which includes firmer springs and dampers, thicker anti-roll bars, a lower ride height by 10mm, stiffer suspension bushes and an altered calibration for the differential.

It’s not cheap but for especially keen drivers it is worthy of investigation. Other buyers may prefer to leave the option box unticked as many may fail to notice any difference on the road.