The BMW M5 is a highly refined ferocious car made better by having undergone a core change. (Photos Lewis Gardner).

For those into irony, think about the M5 – not so much the car per se as the badge.

Marrying a letter halfway through the alphabet with a number halfway between one and 10 surely suggests suggest middle-of-the-road or, at least, some degree of compromise.

Which is a nonsense, of course. The M5 is anything but ordinary, in any respect.

Which is why it looks as staunch as it does sophisticated. What’s the point of hiding those superpowers when everyone knows the back story?

BMW’s M-for-Motorsport Division is surely the best-known of the German skunkworks, simply through being the longest-lived, while car itself also has quite a history, the first having come out in 1986.

The line started with a wallop. The performance gurus, in realising the very good idea of marrying a modified six-cylinder engine from BMW’s M1 supercar into a 535i model, immediately created the world’s fastest sedan in production in its day.

Every Five Series line since has included an M5 and none have been any less extreme, each version having raised the bar further in terms of performance, technology and luxury.

The latest version, known as the F90, takes a different route from its predecessors, nonetheless.

The brand’s trademark rear-wheel drive handling has been venerated with an almost religious fervour that news of this model having gone to four-wheel-drive might be considered something of a sacrilege.

Well, that’s bollocks. If driving time with this product – not least on slippery surfaces – doesn’t change that mindset, I’d suggest they’re not the enthusiast drivers they believe they are. Fact is, this prime mover has progressively become more of a monster, to the point where the latest engine – if allowed to punch out its performance through the rear wheels alone in every operational circumstance – would likely be just too hot to handle.

Thus, the black ops division has come up with a better idea: Allow rear-drive for extreme, at-your-own risk driving circumstances and provide all-wheel-drive for every other scenario. Again, don’t think this is in any way a cop-out. Frankly, the time spent with this car reinforced that this approach is a most sensible idea for this insane package.

In that vein, though, let’s make clear that the test period was not one in which the car was ever operated without some constraint. For one, there were no racetracks involved – that’s simply a caveat that comes with press cars. Yes, of course, it would have been great to have put the M5 on one; even when driving with some degree of abandon on well-chosen public roads, it’s obvious you’re barely touching the core performance potential. It’s THAT grunty.

Also, it wasn’t actually ever driven in the mode in which it reinstates to rear-drive, because that’s an ultra-performance setting which, BMW hinted, if selected might result in issues. Mainly with their insurance cover. They didn’t go into further detail but it left me thinking ‘best not, then.’ Anyway, if you want to see an F90 in full berserker mode, there are numerous videos on YouTube. (BTW, the distributor advice wasn’t just for this writer alone. Everyone who tested this car had to follow it. So, if you read tests that suggest they went to the very edge … well, they’re either voiding the agreement or telling porkies).

About that power. Even though it’s plenty enough for any conceivable everyday opportunity, it was no surprise that in the week of driving BMW announced availability of even more, with an ancillary Competition edition. So much oomph is already evident from the 441kW/750Nm mainstream edition that you wonder why the need for another 19kW. But Munich marketing types know the real sales power comes from that Competition badge and enhanced look.

Those who stick to the general issue model can take assurance their version of the 4.4-litre twin turbo V8 is also special, being not only a development of the previous car’s engine but also delivering the same output as the old stager evidenced in a limited edition called … yup, the Competition Edition.

Anyway, rest assured the output here is already simply colossal for a medium-large family-friendly sedan. Certainly, and quite properly, the drivetrain remains the most impressive aspect of the car; the power reserves are so vast it seems as though little more than a tow twitch, let alone an actual throttle nudge, is enough to take the car from lawful pace to extreme lawlessness.

That’s not to say it is a totally crazed machine. Yet you do learn very quickly that, in any of the lower gears especially, it rolls on power so rapidly that on most roads you probably won't need to keep the throttle fully open for anything more than a few seconds, if that.

What gets you every time is the torque, which unrolls and slams in with tidal wave-like proportion and impact; it is a huge shove totally without lag that just seems unending. On the one occasion when I did properly phat it, the impression was every bit as indelible as the time I got to ride in a two-seater jet trainer. In that, when you kick in, you’re ‘here’ and then, suddenly, you’re ‘there’ … and ‘here’ has become but a tiny dot in the rear view mirror. It’s as though you’re in a cartoon that somehow skips forward a dozen or so frames and happens so thrillingly that it’s hard to keep your brain calibrated. It’s not often that a car feels faster than its claimed 0-100kmh time, in this instance that’s a claimed 3.4 seconds, yet this machine truly does. The only factor that doesn’t come up to speed is the exhaust note. It has the bass notes and roar, but never quite reaches the level of loudness you would imagine to be appropriate.

The wallop and the engineering refinements that contain it is what you’re writing the cheque for, but you’ll be pleased all the same that the car also has enough flexibility to enable low-speed ambling. Well, to a point: It still feels a bit like a race car, not just in the sense that it is always on edge but also because the ride, even in the softest setting, is a bit edgy. Which, frankly, is just part of this territory. You’re buying a tiger, not a tabby cat. Still, aside from the firmness and quite a lot of roar off coarse chip from those wide 20-inch tyres, its refinement levels aren't compromised.

Funny thing is, with BMW having biased drive to the rear even when dolloping it to the front set of wheels, it still feels less like a certain rival that actually specialises in all-paw, not least in 4WD Sport. Yet even when it feels to push more than it pulls, you’re still happy to have the reassurance of all four tyres offering traction as well as grip.

In look, even with its widened haunches and lower ride and all manner of aero enhancements, the model is actually still very executive. The test car’s stunning Marina Bay Blue certainly made it a stand out.

What impacts all the more is the interior, not just the hues but also the quality - it is beautifully finished throughout and though some – including my mate Peter, who still won’t shut about them - may find elements, like the M logos in the backs of the front seats that illuminate when you unlock the car a bit tacky, overall the car has exactly the right level of sporting and plush pedigree you’d expect for the price.

The latest iDrive infotainment system is brilliant, so too the facility to Bluetooth CarPlay and Android Auto while inductive recharging the phone. Small things; big difference.

Does all that make it worth $199,900? Hard to say. The big issue with M5 ownership here is that we just have anywhere adequate where it can be any like fully exploited.

That isn't a fault of the car itself, but it is something that does have to be borne in mind. It is barely awake at 100kmh. The other thing to come to terms with is the car’s sheer size. Though brilliant on a fast, flowing country road, it does feel quite large in that environment.

Chances are that what will most restrict its popularity is that sedans of any kind struggle to achieve much recognition these days. If you could get an X5 that held the same level of performance and dynamic talent – which, let’s face it, is pretty tall order – then you’d see hundreds of these things monstering your rear vision mirror.

Still, knowing that it will be a rare sight by no means erodes its special status.