Giving the world’s best-selling roadster a retractable solid top will very likely hardens up its appeal to newbies, but will traditionalists find it alluring?

For: Brilliantly engineered new feature for a brilliantly engineered car, compliant ride.

Against: The one MX-5 crying out for a reversing camera.

IMPROVING on perfection can’t be really so hard … Mazda, after all, has pretty much been consistently doing just that with the MX-5 since the first stunned, then forever changed, the world.

‘The world’s best budget sports car’ seems a heck of a hefty mantle, but assuredly it’s one this wee beauty has had no trouble carrying over four generations.

It’s now so well-entrenched as the barometer for low-cost driving fun that it probably wouldn’t be wrong to suggest that automotive time should be measured ‘BM’ and ‘AM’. Frankly, nothing ‘before’ – including the Lotus that the first and second MX-5 (or Miata, if you’re an American) copied - was as good and nothing after has been any better.

So, basically, when it comes to MX-5s, they’re all great, and if some are a bit better than others, then you need a micrometer to measure the degree of advantage.

Admittedly, you could say my views are coloured. The Bossel-garage now homes three first gen cars, all built in 1990 … there’s my wife’s pristine Sunday tourer and a pair of club racers, one mine, the other a mate’s.

So I’m prejudiced? Perhaps, but I figure the fact that all three cars are still fundamentally sound and retain start-first-time reliability after all these years and mileage (none having less than 200,000kms on the clock), were cheap to buy and are inexpensive to run simply reinforces why this car is so special.

To the subject of this test, the MX-5 RF. The latter letters stand for ‘retractable fastback’ – it means a car that has won the world over in roadster form now comes with the option of a metal roof that its maker claims has the world’s fastest one-touch folding action.

Does a car that has won its spurs on the strength of simplicity need this complexity? We drive the flagship RF Limited, which in $51,495 manual form as tested costs $4500 more than the equivalent roadster and $1500 cheaper than the automatic.

Design

This generation of MX-5 is one sweet-looking car, potentially the best-dimensioned one and probably the most stylish.

It is as petite as the original and yet, and while as confined inside as it has to (and should) be, is nonetheless more comfortable for tall drivers. The driving position is almost like that you’ll find in a junior formula racing race and you feel connected even before the engine starts.

Mazda has spoken often about how hard it worked to recapture the essence of the first car with the gen four model, not just in feel but also in scale. They cracked it and, though the look now is quite different – in simplest terms, the bits that were curved once are more angular now - when lining the oldest and newest up side by side it’s not difficult to pick them as being from the same family. Certainly, the new roadster is just like the old in that it is easily as handsome with the roof up as it is with it down. That’s not something that many soft-top cars crack.

So what happens when it goes in a different direction and adopts a quasi coupe-like body styling with a targa roof that folds away electronically?

Some say it looks better when keeping its top on than in al fresco mode, whereas the roadster is pretty decent at either extreme, and one mate who also owns a first-gen MX-5 (yeah, there’s a crowd of us) instantly called it a junior Corvette, which seemed a bit of a stretch to me given the Hiroshima product is clearly a lot more truncated. Still, he is a bit squinty, so …

I think the roadster format is more attractive but maybe that’s just familiarity. Perhaps had Mazda put out the RF first, then thrown in an open car, I might have sided with the hardtop, because the additional metalwork does add very naturally.

In a way, this is third time right. The first gen car, after all, offered with a hardtop that had to be unbolted and left at home when you wanted to run with the wind. The previous model got a mechanical hardtop roof, but it was heavy and not anything like as clever as what we get now.

Anyone with an appreciation for good design and engineering will love to demonstrate its operation; the beautiful ballet of its synchronised operation is quite spell-binding.

On the other hand, that whole thing about the car’s simplicity doesn’t apply here. To put a solid roof over the occupants’ heads has required a tremendously complex flying buttressed arrangement of aluminium, steel and plastic.

First, you’ll want to focus on those rear pillars, which have a coupe-like look in profile yet in reality are thin 'flying buttresses' that wrap around the bootlid, leaving an upright rear window and flat rear deck, just like the roadster.

Until you press the control button, of course. As the top retracts, with quiet whirrs and hums, then the whole rear section lifts up out of the way, allowing the middle and front panels to stow. Then the buttresses click back down into place. All in a world-class 13 seconds.

What’s left behind looks a little like a targa-top arrangement, and effectively would be were it not for the rear window stowing itself below deck too, leaving a small, transparent wind deflector in its place.

Drawbacks? You’ll always meet some worry warts (sorry, dear) who wonder what if something fails, or someone bends it (potentially possible as the bits are quite light) or, I dunno, an elephant sits on it? Well, who knows. But I have faith in Mazda’s ability to build things properly. The rest is just chance.

The car needs to be all but stationary for the roof to operate. If the speed creeps above 13kmh it’ll down tools and freeze until the speed slows. The apparatus adds weight of course, but ‘only’ around 45kg. Not much, then, though this is a car in which every gram was considered during development, on the grounds that some purist owners would be so finetuned to its exquisite balance that they’d drive without loose change in their pockets lest it affected the handling.

Bootspace is pretty much preserved too; the RF has 127 litres compared with the roadster's 130 and the compartment shape appears to be a touch deeper and a shorter, but from what I can tell you’ll get as much (preferably soft-sided stuff) in one as in the other.

Otherwise, this hardtop cabin environment is the same as the roadster’s. The MX-5 doesn’t claim to be a luxury car and, even though this cabin is better protected from the elements than the roadster’s, it still has those hard, weather-resistant plastics. The Limited nonetheless does feel less spartan than the entry offer.

It starts, as you knew it would, with leather that offers a better appearance than the base car’s cloth, though to my mind I figure the seats are just a touch more comfortable in their more utilitarian format.

The Limited level offers automatic headlights (including high-beam control) and wipers, both of which work extremely well, heated mirrors, keyless entry, climate air conditioning, auto-dimming rearview mirror, lane departure warning and, not least, a nine-speaker Bose sound system with speakers in the head restraints.

Driving

With the MX-5, this is what it is all about, so it’s best to start by saying that the RF, dynamically-speaking, is no less enjoyable, generally-speaking, than the highly-rewarding roadster.

As with the roadster, you revel in the car’s absolute spirit. The ‘snickety-snick’ close-ratio, short throw, six-speed manual transmission is a delight, the sharp turn-in, the avalanche of feedback and the car’s darty yet generally predictable nature are all fantastic. It’s not a hugely grunty car, but that’s okay. The MX-5 has always delivered impression that it has been created to provide most of its thrills at sub jail-worthy speed.

Mazda effected quite a few changes to compensate for the roof job. To directly counteract the higher centre of gravity and altered weight distribution, for instance, it gets a thicker front anti-roll bar and altered front damper settings, along with different rear spring and damper rates.

The central chassis cross member has been altered too, to balance the ratio of stiffness front to rear.

The whole idea is to maintain the same handling characteristics as the fabric-roofed car yet, on the same roads on which I drove the 1.6 and 2.0-litre roadsters, the RF seemed a bit more settled and maybe a touch less sharp, response-wise.

For me, there’s a sense that the balance is affected by the roof’s position – the car feels more neutral when the lid is in situ above your bonce than when stowed. Body roll is more tightly in check and, intriguingly, this flatter cornering stance isn't at the expense of ride quality, which is perhaps more supple than the roadster’s.

All this sounds like a world of change, but really it’s not, because it’s the MX-5 we’re discussing. With the roadster and RF versions, change is measured in microns, nothing greater. You truly are splitting hairs.

There’s no discernible difference in performance. The 1.5 is not a choice here, as it is in the roadster, probably because of the weight difference. It’s a shame because the smaller unit is a fantastically effervescent thing.

In saying that, I’d personally plum for the larger motor anyway. Its acceleration is more consistent and, more importantly, it has much stronger mid-range torque; another 50Nm at the same engine speed makes it easier to sit behind in general driving and, more importantly, allows for the sense of greater thrust when pressing on. Though you have to row the box to get the best results, peak power is also more accessible, being available at 6000rpm - still high 1000rpm lower than with the entry engine.

So, the big question: RF or roadster? That I’d go for the latter has less to do with the dynamic side of things than other factors.

There’s no getting around the fact that, in addition to being a compact car, this generation MX-5 is quite cosy. And yet, though I’m tall and carry more weight than I should, the NG roadster is pretty good for me. There’s decent legroom and my head is below the top of the windscreen. True, when buttoned up feels more like a capsule than a car, yet it is liveable for me.

The RF? Not so much. Yes, I know that sounds wrong because, for one, it has 5mm more headroom. And everything below the beltline is roadster identical.

That it definitely feels more enclosed is not surprising, given you’ve a whole superstructure behind your head. But I found it more challenging to enter and leave with any sense of dignity. I think because of the buttresses, which forced me to go further forward into the cabin before you settle back and down. Of course, I’m talking about it with the roof in place: That’s how it should be, because the whole point of having it is to provide extra security.

It was easier when the top is out of the picture, but again not as good as the roadster. There are three solutions to this: I can lose height (er … no), lose weight (I should, yet … erm) or buy the roadster.

Anyway, my own problems weren’t the turn-off. It was more a sense that the roof provides a solution to stuff that roadster drivers really don’t consider to be problematic anyway.

Like? Well, refinement. Yes, when driven roof up, the RF is quieter, road noise in particular being reduced. Conceivably, a long-distance drive would be less tiring in the RF than it would be in the soft-top. But who wants to drive an MX-5 long distance? Nothing else about it points to its design and delivery points to it being great for this.

Strange as this is going to sound, driving roof down, it’s the roadster that is less noisy. Yeah, I know, that sounds all wrong … but it isn’t.

It’s a given that an open car will have wind noise and turbulence, but with the roadster most of that occurs above the boot, whereas in the RF, it’s a lot further forward: Right behind and just above your head, in fact.

So put up the side glass, right? Yup, that delivered an effect .. but not quitev what wqe were after. Rather than quieten, if anything the pitch of the wee maelstrom intensified. (Apparently, this is a bugbear with the latest Porsche 911 Targa which – wouldn’t you know – has the self-same roof design). Weirder still, we found there was still wind noise even when the roof and windows were closed.

So there’s that. Then there’s the fact that side and rearward visibility is so worse in the RF. Over shoulder visibility in the soft top isn’t great, but those RF buttresses simply block the view to things you really want to be looking out for. Like traffic approaching at intersections. And what’s behind when you reversing out of a carpark. Basically, you are flying blind with the latter. It’s the one MX-5 that cries for a reversing camera.

Verdict

Mazda NZ reckons the RF has broad enough appeal to account for 90 percent of its projected MX-5 sales for 2017. They’re smart people; so could well be right.

Then again, globally the roadster/RF mix is expected to be more like 50/50. I also note that, in the club scene, roadsters are the go. You just don’t see anything with a hard top.

I love the MX-5. I certainly don’t dislike the RF. But I think the roadster is just better. The hardtop fixture is a great engineering feat, no argument.

Then, again, so too is the roadster’s soft top. Which, by the way, takes just three seconds to open or close and simply relies on the strength of your left arm. Sorted!