And how it can haul. In real-world terms, the M5 is considerably faster than the car it replaces by dint of its more accessible performance. BMW claims 0-62mph in 4.4sec, but I won't be surprised to see independent tests better this. It certainly feels faster, and with its superb traction, heroic acceleration and rifle-action gearchange, the new M5 is able to sustain high speeds on roads that would have worried its more firmly sprung predecessor. Its in-gear qualities are something else again. In fourth, it'll run from 50mph to 75mph in 3.7sec, and just 8.6sec after it reaches 62mph it hits 124mph. Top speed is limited to 155mph, and there's an optional M Driver's Package to bump it up to a limited 190mph.
So it is fast. Fast enough to be a real threat to your license. But what really distinguishes the new M5 from every M5 that has gone before it is the enormous flexibility of its power delivery. Bury the throttle at anything beyond 1500rpm and it surges forward with immense force. Given the heady output, the tractability at low revs is staggering.
It's a vastly different driving experience from the old M5, whose performance relied heavily on your level of commitment to extract it. This new model is, for the most part, even more thrilling from behind the wheel. Yet it doesn't ask for any special favors. The performance is omnipresent and passing is truly effortless, helped in no uncertain part by the effectiveness of the new gearbox. I'm not sure how BMW has done it, but the shifts are racecar quick, accompanied by an alluring bark of exhaust on full-throttle upshifts and a hearty blip on downshifts.
The added flexibility does have its drawbacks, though. Chief among these is a curious lack of crescendo in its delivery. Because the torque is developed across such a wide rev range, the engine doesn't feel much stronger at 6000rpm – the point where peak power arrives – than it does down low. The shove is colossal, but it is also oddly constant. Among the many delights of the naturally aspirated engine in the old M5 was the way its intensity grew in line with the number of revs it was asked to carry. The new turbocharged unit is clearly more user-friendly but it lends nowhere near as much character, nor does it possess the rabid throttle response of the old M5.
The best part of the new M5, though, is not its outright pace but its agility. The overall feel is determined both by the damper mode chosen and by how willing the driver is to alter the stability control system, which offers three settings: default, MDM (M Driver Mode) and completely switched off – the last of which requires the button to be depressed for three seconds.
In default mode, there's a lot of intervention from the stability control, which has clearly been calibrated to provide a wide safety net. Switch it into MDM, though, and the handling instantly becomes much more fluid in nature. I was worried that the big engine and all of its ancillaries might make for a nose-heavy cornering feel, but I was wrong. The M5 feels wonderfully balanced and more neutral than the car it replaces. There's less initial push at the front on turn-in and grip is immense, but with all that torque on offer the M5 is a willing sideways companion when you switch the stability control off. There's always a sense of balance to the chassis and the breakaway is telegraphed with such clarity that it all but urges you to steer through corners on the throttle.
The aluminum-intensive underpinnings, with the uniquely arranged double wishbone front suspension and heavily modified multi-link rear end, offer superb body control. There is a moderate degree of lean as you guide the M5 into corners, but its actions are wonderfully progressive, thanks to terrific damping that ensures any movement remains within a tightly dictated range. Where it really impresses is in its ability to settle quickly when faced with crests and undulations, and there is sufficient give to ensure it doesn't fight the road.
There's also an impressive suppleness, thanks to the variable damping. Despite the lack of compliancy in the tires' sidewalls, the underpinnings manage to retain a good deal of composure, seldom allowing anything more than a sharp ripple to upset progress. In this respect, it's much calmer and more relaxed as speeds rise than its predecessor.
It's only the steering that disappoints slightly. The speed-sensitive hydraulic steering, geared at 2.7 turns lock to lock, is an improvement on the electro-mechanical arrangement used by standard 5-series models, offering a more convincing feel and greater levels of feedback. But it possesses a lifeless feel around the straight-ahead. Once you've negotiated this, though, it's much more alert.
If there's one thing you do in the not-too-distant future, make sure you sample the new M5 in one way or another. In many respects it's a landmark car, and the fast car competition – Audi, Cadillac, Jaguar, and Mercedes-Benz among them – will be scratching their heads as they attempt to come up with a reply. The sheer potency and accessibility of the new engine alleviates any lingering doubts about M division's decision to turn a 25-year tradition of naturally aspirated engines for the M5 on its head.
However, the engine is only one component in a complete and utterly compelling package. What also makes this car so special is its overall agility, breadth of ride quality, superb refinement, practicality and great quality. With a 21-gallon fuel tank and combined cycle fuel consumption of 28.5mpg, it is not only the new performance sedan car of choice but also the perfect cross-continent express.