Twin Test: Porsche 911 GTS v Mercedes-AMG GT55

And even when you’re not launch-controlling it away from the lights, the throttle response is still likely to take you by surprise until you’re fully dialled in. It’s just there, a twitch of a toe away, proving there’s no need for anything more than a single turbo so long as it’s A) electric, B) allied with a hybrid drive and, C) the size of a medicine ball. So while there may be plenty of good reasons to spend the extra on a twin-turbo, er, Turbo, don’t do it through fear that a single turbo motor must be prone to lag. Prior to this GTS, it had been over 30 years since Porsche’s last single turbo 911, and those days are long since past.

The Mercedes takes the opposite approach, so languid in demeanour it’s almost louche. If the 911 is all lycra shorts and running vests, the AMG sports a velvet smoking jacket and co-respondent shoes. But that noise! This car sounds better on start up than do most sporting engines as peak power arrives, and I absolutely include the 911 in that. The flat-six still sounds good, really good in fact, but something in this new engine – probably the need to comply with ever-more stringent emissions and noise regulations – has blunted its chainsaw edge, just a touch. The V8 from across town has no such issues.

Indeed I’ve been wondering how many tenths of a second I’d be happy to trade to keep that voice, and the fact is it’s probably more than the number that separates the Mercedes from the Porsche. As we have had cause to comment ad nauseam on these pages in recent years, there is a ceiling to what level of performance is sensible, appropriate or even feasible to deploy on the public road and even the AMG has its head right up against it; the Porsche has punched through the MDF and is currently reminding itself what its attic looks like. The Turbo S? I have no idea but I expect it’ll involve some new roof tiles.

The Mercedes offers three grades of progress: woofle, thunder or roar. The first and third have their merits, but it’s the middle approach, when your foot is exerting enough pressure to get the motor’s attention but insufficient to make it go hunting for another gear that’s best. There’s plenty of progress here, and it is of the highest quality.

The 911 is far more urgent, egging you on, almost daring you to press harder, go faster and there is a relentless nature to the way it deploys its potential its rival cannot match. It has the better transmission too, a typically whipcrack Porsche dual-clutch, against Mercedes’s unconventional and still excellent automatic where a series of wet clutches take the place of the torque converter you’d have otherwise expected to find. Even so, on powertrain alone, I’d call it advantage Mercedes.

That the Porsche gets it all back, and some more, when the road no longer runs straight is perhaps not the greatest surprise you’ll receive this week. Look at the weight, the wheelbase and, above all, the job description and it all points to the 911 being, as usual, the best car of its kind when the going gets interesting. And they do not lie.

I think one of the reasons the original AMG GT suffered more in comparisons such as this is that it was so clearly trying to out-911 the 911, a feat that remains unaccomplished by any car over the last 60-something years. It had a certain edginess to it, which was indisputably exciting but no real substitute for the feel and poise of the rear-engined legend. It always came off second best in the more challenging environments. This AMG GT does not even dispute the territory and, perhaps curiously, is all the better for it. It’s bigger than its predecessor, much heavier too and slower to react. The mass and its driven front wheels mean the steering, while well weighted, accurate and linear in its responses, does not flood your fingers with feel.

But nor do you feel any longer the need to grasp the wheel quite so hard, to be quite so alert to the possibility you might suddenly find yourself quite busy when you never really intended to. This new AMG takes a very different approach: as reliable and consistent as they come, and if that means it doesn’t thrill in quite the same way, and not always for the right reasons, then so be it.

I quite like it for that, particularly as there’s never any shortage of grip, the four-wheel steer confers a level of agility you might not expect even though it never really succeeds in shrinking the car around you, and the body control is rarely less than entirely fluent and reassuring.

But it’s no 911. For the true enthusiast, everything – and I do mean everything – about the way this Porsche handles is just better. It’s not so wildly ahead in any given area that you wonder why we even got them together on the same road, but the cumulative effect is not only undeniable, it is insuperable.

What is interesting is the way the hybrid joins in the fun, that new found immediacy of throttle response proving so well suited to the character and response of the chassis. What is also interesting is that when I attended the original launch of this second-generation 992 GTS in 2024, they also wheeled out the standard Carrera and while the GTS was obviously far quicker on both road and track, the lighter, more nimble base car was equally clearly the more fun to drive.

No such problems here: it really doesn’t matter that the GTS has more raw grip than the AMG or that its traction is at least as good despite having (in this case) half the number of driven wheels, because on public roads these are not limitations in either car. What does matter, and matters a lot, is the way the Porsche involves you in the process, putting you at the heart of the action, creating this sense of the two of you being in it together. You never get that bi-directional relationship in the big Benz: you tell it what to do, it does it, obediently, faithfully and without demur. But that’s about it. In the Porsche there’s a proper conversation to be had because it’s always relaying information to you. And ultimately, if I may get briefly anthropomorphic, it is that meeting of the minds, that sense of being at one with your peer that provides an experience not merely for the there and then, but which lives on in the mind long after the car and you are back home and safely tucked up in bed.

Is this the place to talk practicalities? I think they matter, because their provision is so often the determinant between whether a car gets driven or not. The most regular criticism we’ve heard about the Alpine A110 is not actually that it doesn’t have a manual gearbox, but that its boot is so small it really restricts what you can do with it. The good news is that both these cars have sufficient storage space under bonnet or boot lid and on their back seats that there is no normal journey you could not do in either, including a fortnight’s cruising around Europe.

But the AMG goes further. Its boot is not only well over twice the size of the Porsche’s, but you can fold the rear seats forward and liberate enough space to house, for instance, four pairs of skis, and at once an all-new use purpose becomes available which the 911 would require a roof rack to meet. And while both are very definitely 2+2s, the long suffering (not to mention quite tall) Mrs Frankel did do 150 miles in the back of the Merc and still emerged with blood supply to all four corners and her sense of humour intact. I’ve had dozens of 911s here over the years and no way would she have made that journey in any one of them.

I’ll spare you the lengthy denouement parlour extemporisation and tell you straight: the Porsche 911 GTS wins. It’s not a Pyrrhic victory, nor can the Mercedes-AMG GT 55 claim some approximation of a moral victory. I’m not that interested in the Porsche being quicker, nor even that it’s cheaper (because so much will depend on the option spend), but that new engine and in particular the way it energises the chassis, is very special. At its heart there is a driving experience here its rival cannot match, and it’s good enough at the boring stuff still to make sense in that way 911s always have. But the AMG runs it closer, as close as did the likes of the original Audi R8 and Aston Martin V8 Vantage, albeit for dramatically different reasons.

This Mercedes is a truly likeable car, one whose looks make a promise you can’t quite believe the car will be able to keep, right up until the moment it does. It’s an easier car to live with than the 911 (unless trying to park) and by that I don’t just mean it’s more spacious in the back and boot. It’s ergonomically better, its interior looks more attractive and feels more expensive and were I returning from a long trip I know which one I’d rather find in the long stay car park waiting to whisk me homeward.

So congratulations Porsche: your determination to keep the 911 relevant, technologically cutting edge yet still and always a 911 deserves the highest praise. But so too does Mercedes deserve to be recognised for what it has achieved, and rewarded in the marketplace also, more so than any AMG GT that went before.

Photography by Malcolm Griffiths

Does the Mercedes-AMG GT 55 or Porsche 911 Carrera GTS sound like your dream car? If you are looking to finance an AMG GT, 911 or any comparable car, see what JBR Capital can do for you today. They are dedicated to serving car enthusiasts like you, offering personalised finance solutions tailored to your specific needs. Forget the one-size-fits-all approach – with JBR Capital, you’ll speak to them directly and they will work with you to create a finance package that fits your needs.

Find out more about Mercedes-Benz finance, Porsche finance or use JBR Capital’s Finance Calculator.

JBR Capital is authorised and regulated by the Financial Conduct Authority.