We’re not sure why the adoption of the name shared with that of the Gunnersbury-Llanedi motorway should cause such mirth in this country when the M3 and M6 do not, but the M4 badge does just that.

There is at least some significance to the single-digit increase. This M Series coupé is some 4671mm long, which represents a 53mm increase over the departing M3 coupé. It’s also 180mm longer than the generation before that, the E46, and 326mm – a full a foot and a bit – longer than the original E30 M3. This is a seriously large car.

Nic Cackett

Nic Cackett

Road tester
New car, new badge. With the coupé likely to massively outsell the saloon, expect this insignia to quickly become part of the landscape

Nonetheless, BMW says it targeted the weight of the last six-cylinder M3 when it set out to create the M4. Equipped with the standard M DCT seven-speed dual-clutch automatic transmission, our test M4 weighed in at 1610kg. That’s only 10kg lighter than the M3 we tested in 2007, but that was equipped with a manual transmission.

It’s also telling how difficult it is becoming for BMW to retain its trademark 50 percent front, 50 percent rear weight distribution. Removing weight from the rear of the car is easy enough (by using a composite tailgate, for example, as here), but it’s rather more expensive to remove it from the front.

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Our test car was 52 percent biased over its nose, which is no bad result given that a 3.0-litre straight six engine with two turbochargers resides there.

Ah, the engine. The capacity has dropped by a full litre over that of its 2007 predecessor, yet power is up from 414bhp to 425bhp, while torque rises from 295lb ft to a fairly whopping 406lb ft. If you add the Competition Pack the M4 gains an additional 19bhp while its torque remains the same. The newest addition to the range is the M4 CS, which gets a peak 453bhp driven through its rear wheels, while heading the range is the limited edition GTS which produces a monstrous 493bhp.

It is developed from 1850rpm and is available until 5500rpm, rather than at the 3900rpm of the V8. The red line has decreased from 8500rpm to 7600rpm in the process, but all of the headline figures are more compelling than they were before. The fitment of two turbochargers has increased the natural lethargy of the M4’s six-cylinder engine, so BMW has gone to great lengths to mitigate the lag.

The most effective way to do so is to minimise rotating masses and therefore inertia, which is why there are two small turbos rather than one big one. They’re both single-scroll units. Twin-scroll turbos split exhaust gases from the cylinders until they reach the turbine, but you can’t really do that between an uneven number of cylinders.

Ancillaries that might in past times have been driven off the engine — such as the power steering, obviously, and the pump that drives coolant to the turbo bearings when the car is stationary, less obviously — are here electrically driven to further reduce the load on the engine.

Farther down the line, the driveshaft is constructed from carbonfibre, which makes it 40 percent lighter than that of its predecessor, while half-shafts are hollow and therefore spin more easily than on the previous-gen M3.

Elsewhere, other changes deemed worthy of BMW’s M division include a carbonfibre roof and output shaft, aluminium suspension components, an ‘active’ differential (in the form of an electronically controlled mechanical limited-slip differential) and an aluminium bonnet and wings.

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