Let’s get our priorities straight. When it comes to four-seater convertibles it’s all about style, surely. You want to make a statement… cue pouty selfie face now. If you’re a boy racer and it’s hardcore performance you’re after there’s no shortage of fixed roof options from AMG and M division to get your rocks off. Yet, with the roof stowed, noise is as much an envy generator as cosmetics, so a sonorous six-cylinder is better than a muted four-pot. That’s how we come to these willfully overpowered droptops: must look good, must sound good, must just about stay on the road. Let’s commence.

Although first introduced four years ago the Beemer is arguably still the most attractive of the duo. The proportions are simply spot-on, the design strikes a perfect balance between elegant (roof up) and extrovert (roof down), and while less adorned than the Merc, the build quality could teach the newer car a thing or two about robustness. The Mercedes, by comparison, features diamond grille as standard but every AMG sport kit and LED DLR light option known to mortal man and looks great… head-on. However, it’s simply too fussy from other angles with its upswept profile lines, pimply bumpers and hunched-over hind quarters. In terms of straight-up street cred it’s the BMW that scores eleven out of ten for that elegant ocean liner look in profile.

Looks, of course, are subjective; performance is less so. It is here that the 440i is brisk but the C43 is marked certifiably quick! Top speed is limited to 250kph across the board, but the Benz hurls itself to 100kph in 4.8sec, 0.6sec faster than the BMW. That’s despite a 125kg weight penalty over the 440i. Both feature 3.0-litre engines, both forced induction, but the 4 Series can only muster 240kW/450Nm while the C-Class puts out a meaty 270kW/520Nm. And let’s not forget the Merc has 4Matic AWD and a nine-speed automatic gearbox to transmit that power to Tarmac. Even the torque plateau is near-as-makes-no-difference, there’s little to separate them in terms of real world drivability either, aside from the extra punch from the Benz of course. But numbers tell us only so much…

We’re in Piketberg, inland from the Cape West Coast, devoting a day to testing these droptops’ dynamic nuances. Off the bat this feels like Mercedes country, weirdly: sun-dried, pock-marked Tarmac that adjoins the sleepy hamlet to the start of Versveldpas has one fast sweeping corner leading to the next. The C43’s 4Matic cannot contain its glee at the g-force challenges. Roll, yaw and body flex are kept safely in check in taut Sport+ mode; grip from all four driven wheels is bountiful. Pity the steering feel is a little passive, combining a bizarre lightness and lifelessness off centre. Cornering attitude is I-go-exactly-where-you-point-me; and relentlessly fast, even with the AWD weight penalty. The white BMW is rendered but a speck in its rearview mirror.

The 4 Series looks a picture but it’s not faring well in this tricky terrain; struggling for grip, ruffles of revs spiking and dipping as the stability control works overtime trying to summon grip from the rear wheels. A few km up the road it enters its zone though. The last two thirds of asphalt to the summit of the Piketberge is textbook Beemer territory – smooth and technically demanding. It’s a substantial 125kg lighter than the Benz but in this moment it feels about 300kg better off. Glide into a turn with excess speed, lift off, and wait for the BMW to recover in one gracious arc, then unwind steering lock again. This is handling! There’s quicker steering, eager gearing that tries to make up for its torque shortfall and a sharper chassis. The rasping blare from the long-legged straight six isn’t hard on the ears either. The frontend feels connected to your palms on the wheel and your buttocks with the rear axle. All these factors culminate in the more tactile, more entertaining drive. Nevermind that while the 440i’s tail wriggles around it’s making no significant inroads into the C43’s lead. If anything Wa’Benzi is romping further ahead with better traction out the tighter corners.

The C-Class Cab is no champion when it comes to the feels but the chassis remains neutral, traction is confidence inspiring and the V6 engine is a masterpiece… even forgiving the fact it’s not actually a hand-built AMG and therefore goes against Affalterbach’s own long-publicised ethos. It has more muscle where it matters, doesn’t need to rev too high and makes all the howls, pops and gurgles Jaguar popularised with its loquacious V6-powered F-Type. Subjective as this next statement may be, it feels out of keeping with a Mercedes-Benz droptop and doesn’t gel with segment expectations. It’s almost too fast: front tyres overcoming their grip and understeering, inertia reel seatbelt trying to strangle you in the hairpins. It’s the ‘Flying Dutchman’ when an elegant ‘Lady Moura’ superyacht will do.

So, who wins? Of course outright speed and driver experience is crucial but it’s the finer margins of elegance and desirability that govern our winner. The Mercedes-AMG is the one to beat against a stopwatch, making it loom larger on the performance front than expected, but it doesn’t possess or drive with the style of the 4 Series Convertible. The BMW is more affordable as well, making the fact it possess the unique qualities to succeed as a four-seater poseur mobile all the more gratifying.

In a nutshell – BMW 440i Convertible

Highs

The ultimate driving machine, even as far as four-seat convertibles go. Pips the three-pointed star for finesse, feedback and good looks.

Lows

Hardtop roof a bit cumbersome; can’t be dropped at a set of lights.

Figures

• Engine: 2998cc, 6-cylinder, turbo
• Power: 240kW@5500rpm, 450Nm@1400-4500rpm
• Performance: 0-100km/h 5.4secs, top speed 250kph
• Tyres: 18-inch alloys, 245/40
• Economy: 7.2l/100km
• Transmission: 8-speed auto
• CO2 emissions: 159g/km
• Price: R977 300

In a nutshell – Mercedes-AMG C43 4Matic Cabriolet

Highs

Benz beats the Bimmer on grunt and loves to devour a mountain road, if you’re into that sort of thing in your cabrio.

Lows

Awkward looking with the roof up or down. Some might say not strictly an AMG.

Figures

• Engine: 2996cc, 6-cylinder, turbo
• Power: 270kW@5500rpm, 520Nm@2000-4500rpm
• Performance: 0-100km/h 4.8secs, top speed 250kph
• Tyres: 18-inch alloys, 245/40
• Economy: 9.9l/100km
• Transmission: 9-speed auto
• CO2 emissions: 194g/km
• Price: R1 058 736