Before Jaguar decided to stage its polarising reinvention, there was a time when marketing suits embraced that caddish and villainous reputation the growler marque held.

“Good to be bad” was among a series of advertising taglines. At the time it had snarling V6 and V8 performers to back up all this hard talk, deployed under the hoods of fearsome saloons and striking sports cars that seemed to lend themselves to activities of wrongdoers on the silver screen.

Not many automakers these days are so brazen as to trumpet their naughty sides. It got me thinking, hearing the Ford Mustang Dark Horse fire up in our office basement the other day (setting off a Chery's alarm in the process). This wild pony is designed to pander entirely to the part of your makeup Sigmund Freud referred to as the id.

A well-adjusted ego mediates impulses and desires, prompting you to start your Mustang Dark Horse in the “quiet mode” setting that Ford engineers have thoughtfully added to the menu. But the unchecked id will have you starting up the Horse in its loudest tune on a cold morning, just nje — to hell with the neighbours!

Truly, this is a car that could bring out the wildest streak in a person. Like the old Jaguar spiel, sometimes it feels good to be bad.

Late last year when Ford introduced the Dark Horse to the South African media, it took us to Lesotho's stunning twisties for an initial driving experience. The thundering coupé left Basotho ponies frightened and cowering, as it tore up the tiny country's spaghetti curves, through mountainous landscapes.

We flew back across the border with a better understanding of why, at R1,508,000, the Dark Horse required a further R201,000 over its standard GT counterpart.

First off, the extra money gets you a unique exterior dressing: a more purposeful body kit, including fang-like bumper inserts, trapezoidal nostrils, side skirts, a rear diffuser, 19-inch aluminium alloys and a rear wing. Eagle-eyed fans might even notice the forward-facing horse emblem, the first time such a depiction has been used on the Mustang (it had always been the galloping side profile).

Aside from darker accents, a flat-bottomed, suede-trimmed steering wheel and a numbered build plate, the cabin remains as it is in the GT. That means full digitisation and a bounty of amenities; everything from a heated steering wheel to ventilated seats and integrated navigation.

But the upgraded hardware under the skin is sure to be of more interest to those committed enthusiasts. At first they might have been disappointed to read that the local Dark Horse outputs do not match those of the US-market model (386kW/566Nm).

Our car serves up 334kW from the famed Coyote V8, which is still 6kW more than the regular GT. The torque figure remains the same: 540Nm. Like its lesser sibling, the Dark Horse uses a 10-speed automatic, which feels a tad more responsive in the way it dispatches shifts.

As alluded to earlier, it has a far more distinctive acoustic character, thanks to the fitment of a performance exhaust system with active valves and different sound profiles.

The claimed 0-100km/h time is 4.4 seconds. When group motoring editor Denis Droppa strapped the testing equipment onto the Dark Horse at Gerotek, it registered a 5.2-second dash to 100km/h from standstill, not a poor show if we are keeping expectations managed.

Yes, there are lighter, more efficient turbocharged rivals from German brands, but at the moment nothing competes with the soulful character of the blue oval muscle car. Amplified in Dark Horse guise.

The current GT marks a considerable leap over its predecessor where dynamic abilities are concerned. And the Dark Horse manages to tidy up those attributes further, with its Brembo discs and calipers, beefed-up front shock absorbers, stronger strut tower braces and meatier rear sway bars. Like the GT, it retains the Torsen limited-slip differential and MagneRide adaptive damping system.

Of course, the firm ride quality leaves you feeling those varying road surfaces of Johannesburg, more an indictment on our infrastructure than a slight on the car.

It is certainly a more cohesive handler than former Mustang iterations. Still, buyers who might have become desensitised by clinical Teutonic performance options with all-wheel drive layouts may need some time to fully acclimatise to just how brutish the Dark Horse can be.

This is a powerful rear-wheel drive instrument after all, meaning you can find yourself facing the wrong way on Beyers Naudé Drive without much provocation. The Dark Horse keeps keen drivers alert, excitingly loose in the tail, with an addictive soundtrack goading them on. Driving it sedately (and quietly) is a challenge.