The road ahead looks inviting. First, it’s completely devoid of traffic. Second, the first, straight bit soon gives way to a series of serpentine twists and turns that dip into the valley and then crest the rise ahead.

From behind the thick-rimmed steering wheel, I can hear, even feel, the V8 engine’s muted growl. It’s an impatient sound, rich with the promise of pent-up power and pedigreed performance.

The stubby gear lever is set to manual, the left shift paddle has already engaged first gear. A tap of the small, red alloy M-lever on the steering wheel invokes all the key go-faster settings, tweaking engine response, suspension, steering and stability control for maximum attack.

Deep breath. Left foot on the brake, then hit the loud pedal with the right, and … go! The big sedan scorches off the line, the gumball Michelins scrabbling for traction despite the clever assistance of the high-tech all-wheel drive system.

The rev counter needle is rocketing around the dial, demanding second, third, fourth gear in rapid-fire succession. Meanwhile, the straight stretch of tar has been gobbled up in a pull-zoom blur of velocity, and I just manage to turn into the first right/left curve combo.

Yes, things happen fast in the BMW M5 if you’re brave (or foolhardy) enough to keep the accelerator welded to the firewall. The momentum builds relentlessly, seemingly defying gravity and giving your neck a thorough workout.

The steering that initially seemed a bit too heavy (certainly by modern electric power steering standards) now communicates its dynamic messages with just the right amount of gravitas, underpinned by the equally unequivocal feedback from the tautly poised chassis.

As the BMW unwinds the next few corners with gravity-challenging tenacity, it’s the agility of the four-door that eclipses even its insistent acceleration. You know that the all-wheel drive system is feeding enough urge to the front wheels, and balancing the ratio between the rears, to keep things tidy – but it never feels intrusive.

The steering remains precise, and the rear is just rebellious enough to make you feel like a DTM star, dialling in instinctive counter-steer even though you know you’re not even close to pushing the car’s actual limits.

But here’s the thing: the M5 makes you think like a racing driver. It makes you want to drive like a racing driver. And yes: it makes you believe that you’re good enough to be a racing driver.

It’s as convincing a demonstration of automotive artificial intelligence as any: you may be the one turning the wheel, hammering the throttle, deftly dabbing the brakes. But deep down, you know it’s the car that’s keeping things in control here.

So, what if you’re really that good? What if your surname is Alonso, or Ricciardo, or Ogier (or Van Der Merwe, for that matter)? Well, you don’t have to be the BMW’s techno slave. You can switch off each and every assistance system on board.

Realistically, only a small percentage of M5 owners will want to do that. And those that do, will probably have the skills set, and regular access to a race track, to measure their own mettle against the BMW’s unassisted fury.

For most of us lesser mortals, M’s latest sedan allows enough glimpses of greatness to ensure real entertainment value without becoming intimidating.

Let’s take a step back for a moment and consider some of the salient points that make this sixth-generation BMW M5 special. The aesthetics are, if anything, on the understated side.

Yes, anyone can see that this is no normal 5-Series: the wheels are too big, the tracks too wide, the stance too low, and the air intakes too hungry. Huge brake discs and gutter-sized exhausts are further clues, as is the distinctive M-badging.

But in visual terms, the M5 looks more business class express than racing machine. There’s a suaveness, a quiet confidence about this sedan that’s quite at odds with the extrovert loud-and-proudness of it closest rival, the Mercedes-AMG E63.

What you don’t see are the under-the-skin improvements responsible for the transition from 5-Series to M5. The suspension, though similar in layout and configuration, is bespoke M, delivering levels of tautness and chassis response miles ahead of the standard sedan’s.

For once, it’s worth raising the aluminium bonnet and glancing at the power plant lurking below. Like its predecessor, the new M5 gains its muscle from a 4.4-litre, twin-turbo V8. But again, almost every aspect – from the dual turbochargers and the intake manifolds to the mapping and the exhausts – has been fettled and optimised.

In latest guise, the aluminium eight-potter delivers 441kW and 750Nm – eyebrow-raising stats, for sure, but more so because of the breadth of power and torque on offer across much of the engine speed range.

Put it this way: for all its high-revving splendour, you could keep the engine pottering along at between 3,000 and 5,000rpm in all gears and still enjoy a big slice of the engine’s potential. The torque shove already peaks at 1,800rpm, while max power is on song from 5,600rpm.

The drive system is unique by BMW M standards, too: it links an M-optimised version of the eight-speed Steptronic auto gearbox to an all-wheel drive system that’s rear-biased, in deference to the Bavarian marque’s long-standing loyalty to rear-wheel drive.

However, as those rears start running out of grip (which happens quite easily, given the urge on offer) the drivetrain seamlessly, almost pre-emptively, transfers power to the front wheels. At the same time, torque vectoring varies the amount of muscle between the rear wheels, too.

For those purists who scoff at the assistance of all-wheel drive, and would rather take on the responsibility of feeding 600 thundering horses through the rear wheels themselves, drive can be limited to the rears, only.

As mentioned, you can also switch off the dynamic stability control, but those with less than delicate right foot control can expect leery oversteer and the expensive aroma of the M5’s bespoke Michelin rubber going up in smoke …

For all its focus on blue-blooded performance, the M5 does envelop its occupants in comfort and luxury, too. After all, it is the 5-Series flagship, and its responsibilities stretch further than delivering supercar-busting dynamics.

The test car’s two-tone ivory and black upholstery, together with illuminated M-logos on the front sea backrests, will be on the garish side for some tastes, but the heavily bolstered buckets provide supreme support and comfort, while electric adjustment ensures they’ll accommodate all shapes and sizes.

There’s no shortage of space for rear occupants, making the M5 a full four-seater family sedan (and even five, at a bit of a push). Factor in the generous 530-litre boot, and the BMW could be considered a luxurious and effortless overland express.

As for bells and whistles, the M5 has them all: from a full suite of active driver assistance and safety systems (think blind spot warning, lane departure warning, pedestrian detection warning, and more) to surround cameras that make parking even this large machine in tight spaces a cinch.

There’s a full-house infotainment system with benchmark connectivity, touchscreen and voice control interfaces, Apple CarPlay, satnav, Bluetooth, and USB and auxiliary inputs. If your smartphone is compatible, inductive charging is also on offer.

You can illuminate the interior in a choice of shades at a brightness level you prefer, and if you’ve opted for the fancy Bowers & Wilkins audio system, you can choose to light up those drivers, too. Of course, the likes of cruise control and remote central locking are part of the package.

Want to spend more? Rear-seat entertainment is on the extras list, and there are various added-cost interior finishes for those who like a more customised cabin. Bigger wheels and ceramic brakes are options, too.

Put it this way: given that you’ll need R1.7bar to make a ‘basic’ M5 yours, what’s a couple or R100k between friends? This is not a car where budget and pricing will be the determining factor, after all.

However, more than anything else, the M5 is about performance: white-knuckled, pulse-racing, adrenaline-pumping, landscape-blurring, eyeball-bulging performance. For all its civilised appearance, it’s the way it accelerates, corners and brakes that is its real attraction.

Even those used to supercar dynamics will find life behind the M5’s wheel alluring – because, for once, you can experience afterburner-like thrust, neck-wrenching lateral Gs and momentum-defying stopping power while still piloting something that will fit four and a bootful of bags.

That the M5 weighs a considerable 1.89 tons adds a further dash of spice to the performance equation: it injects an intensity, a staunchness to the experience that is quite different from what you’d experience behind the wheel of a lightweight, two-seater supercar.

For those with the self-restraint, there’s also the knowledge that the M5 can fulfil the role of luxury performance sedan with aplomb. Select Comfort mode, mute the exhaust, let the auto ‘box swap the cogs, and the M5 will purr through traffic without missing a beat.

That said, all that urge is only one prod of the throttle away: in the M5, overtaking is almost comically easy, and its instantaneous reactions open up traffic gaps that simply wouldn’t exist in less machinery.

It’s that Jekyll-And-Hyde personality that’s always been at the core of the BMW M5 persona. But in this latest version, Dr Jekyll is more sophisticated than ever, while when unleashed, Mr Hyde’s hooliganism has never been more intense.

Which one wins depends, as always, on the driver … DM

PROS

The ultimate supersedan. Dr Jekyll and Mr Hyde find a perfect but frightening partnership

CONS

Increasingly irrelevant on our crowded, potholed, dangerous roads

VITAL STATS