Twin test: Mazda MX-5 vs Mercedes-AMG GT C

This feature originally appeared in the July 2017 issue of Top Gear magazine.

But the truth is, I don’t much care for convertibles. I like the idea of them, but the reality? Not so much. I can’t hear hands-free calls, they mess up what’s left of my hair, I get sunburn within 12 minutes (even on a cloudy day) and should I choose not to get roof down when the temperature creeps over 15ºC for all the reasons above, people frown and shake their heads at me like I’ve just relieved myself into their shopping bag.

But today is different. The phone is turned off, I’m creamed up like a toddler on Bondi Beach and I’ve gone for an extra dollop of strong-hold gel. Today I’ve been dealt a blinder to untangle a simple conundrum – if being open to the elements is your thing, do you need to spend big to get the desired effect? Does more power, more bling, more noise, more everything necessarily mean more fun, especially on the UK’s uniquely narrow and crumbly roads? Just to be crystal, this is not a direct comparison, cross-shopping between these two cars is… unlikely. This is an exercise to prove that when you focus right in on fitness for purpose, an underdog can punch well above its weight. Enter our disparate pairing…

At the affordable end of the spectrum we have the singularly brilliant Mazda MX-5, the definitive pared-back roadster with only a modest 158bhp from its 2.0-litre engine, barely a tonne for its sparkling chassis to haul around and a manually operated roof. Simple, sporty, manageable, sublime. Yet somehow the prospect of driving one on some of the UK’s prettiest sun-drenched roads isn’t really tickling my pickle right now. It could be something to do with the AMG GT C that’s just pulled up alongside, like some vast silken shark. Wider track and arches from the GT R, low, hostile, it looks spectacular burbling away in the morning light – you could probably park an MX-5 on the bonnet alone.

Mercedes will do you a cooking GT Roadster, but the GT C is the one you want. Taking the best bits from the GT R – the wider track, four-wheel steer, electronic rear diff, adaptive sports suspension, toothy Panamericana grille, louder exhaust, lighter lithium-ion battery – and marrying them with a 549bhp version (28bhp less than the GT R, 28bhp more than the GT S and 80bhp more than the standard GT Roadster) of Merc’s twin-turbo 4.0-litre V8, it’s probably the most focused of the current R8 V10/Turbo S Cabriolet/F-Type SVR crop. But, as we learned from the GT R, although the spec sheet reads like a track special, it should be far more manageable on the road than the sum of its beefed-up parts. This is a Merc convertible after all, so an ability to cruise, as well as entertain, should be a given.

The GT C is like some vast, silken shark. Low and hostile, it looks spectacular

Right now, we’re on Beachy Head Road, up early to beat the Saga tour buses, and strangely I’m not thinking about cruising or entertainment, it’s a game of damage limitation. It feels absurdly wide, wide enough for two accommodating seats, a fat centre console, and surgically enhanced wheelarches beyond that. The steering isn’t helping, either – it’s on constant high alert. This is the epitome of a modern supercar steering set-up: light on feedback, even lighter to turn (even in S+ and Race modes), but with a super-high ratio giving the front end a feeling of telekinetic responsiveness.

So the road, quite literally, isn’t a great fit for the GT C, but with an engine like this you’ll be amazed at what can be forgiven. You don’t need more than the length of your driveway to realise it’s a stonker, all gruff and woofly at idle – like it’s carrying a nasty chest infection – but give it some revs and it makes all sorts of noises to keep you and your neighbours entertained. Forget Comfort and Sport modes, they’re far too tame, go straight for S+ or Race (not forgetting to dial back the suspension to the softest of its three settings) and the exhaust baffles open fully unleashing a snarling crescendo and a 21-gun salute when you lift off. With the roof down and your bottom parked pretty much on the rear axle, it’s almost enough to justify the £139,460 price tag alone.

Hopping into the MX-5 on the same bit of road is like swapping ski boots for slippers. It just fits. It feels like a puppy let off the lead for the first time – a gentle growl from the exhaust, just enough performance to keep you interested and your foot welded to the floor. Of course, the engine is sparrow-like compared to the Merc’s, but with no turbos there’s no delay and whereas the GT C can happily short-shift at 4,500rpm and still be barrelling along at mighty speeds, there’s a requirement to rev the Mazda and waste not a drop of the engine’s potential.

Like the AMG the steering is light, but then so is everything else – the gearshift, the pedals... the whole car, in fact. The AMG is impressively damped and never bottoms out, but it still rides with an underlying firmness, whereas the MX-5 glides down the straights and rolls and pitches around the corners – undesirable for ’Ring records, but wonderfully involving on the road.

Nowhere else are these car’s opposing approaches better demonstrated than with the roofs. The Merc, a whirring mechanical ballet of magnesium, steel and aluminium lasting 11secs and operational up to 30mph. The Mazda is a manual, no-frills, unclip, flip and click arrangement operational up to whatever speeds your biceps permit. Both have the desired effect: bringing the sun, wind and a high-def exhaust note into play.

One word of caution: if the attention a supercar brings is a concern, then a cabrio amplifies it considerably. Sitting at the lights in a coupe at least you’re largely obscured by glass and metal, but with the roof down in the GT C you’re constantly on parade. I find myself not knowing what to do with my facial expression – do I grin like I’m the luckiest guy in the world and I know it, or do I go for something cool and sullen, whatever that looks like? Invariably, I decide a straight-on middle-distance stare and awkwardly drumming my fingers on the door is the way to go.

Right, enough posing, time to find a road with a little more wiggle room, somewhere the GTC can shine. What you quickly realise is how rigid the reinforced chassis feels and how much you can lean on it through the corners. Where width was once the enemy, it now translates to indestructible lateral grip – honestly, you’ll need a racetrack to discover where it ends and the sliding begins. Four-wheel steering on the other hand is just brilliant at any speed – bringing a sense of agility to match that hyperactive steering, it’s like a couple of hundred kilos have just been stripped away.

Yet the MX-5 still doesn’t feel outclassed or out of its depth, because these are the roads and the days it was made for. It has an ability to simplify and distil the driving experience and make everything else seem too complicated and unnecessary. And it’s true, on UK B-roads or around town, the GT C is overkill, but Merc hasn’t taken any shortcuts so it’s a car that feels indulgently over-engineered for the simple process of clipping along with the wind in your hair. Bring a racetrack into the equation and the GT C would eat the Mazda for lunch, but if track days are your thing, we’d go for the GT R anyway. Which all sounds like I’d take the Mazda, but I wouldn’t, I’d have the Merc. Whoever said money can’t buy happiness was a liar.