Mercedes-Benz GLA-Class vs Porsche Cayenne

What's the difference?

With Mercedes-Benz’s vast number of SUVs, there is room for an urban luxury crossover niche, and the GLA delivers in spades.

Indeed, in 250 4Matic guise, it is that rare thing – a high-riding hatch with dynamics to shame most dedicated pocket-rockets. It really is a hoot if you find the right road, regardless of weather conditions. The Benz has towering talent.

However, even without desirable options like adaptive dampers and a full suite of driver-assist safety technology, the GLA is expensive, does not quite carry off the price tag from an interior quality point of view, and struggles to maintain the degree of comfort and refinement expected from a Mercedes – with or without the $3K necessary to score adaptive dampers.

Still, especially because of the way the GLA looks, goes, stops and steers, if you can afford it, you’ll be rewarded. There’s never been a more rounded GLA.

Of all the super SUVs I've piloted, the Porsche Cayenne Turbo GT is the best all-rounder in terms of performance, comfort, cabin technology and style.

As a family car it's roomy, practical and easy to use and drive daily.

As a performance car the Turbo GT is stupidly quick, with the agility of a sports car. Sure, a 911 would leave it behind on a twisty race track, but this SUV is close to having that sportscar experience and keeping your family, as well.

Looking like a mini-me GLC, today's GLA trades some of its predecessor’s edgier design elements like the slammed roof and exaggerated broad-shouldered stance for a more amorphous if elegant appearance. Even with the cliché plastic cladding around the squared-off wheel arches, it’s still a looker.

The net result is arguably the most attractive of all the MFA2 A-Class offshoots. It sits well within the Mercedes hierarchy of SUVs, bringing a swoopy coupe-like silhouette compared to the ultra-upright GLB.

Along with being 30mm wider, it’s also visibly taller than before, with a handy 213mm of ground clearance compared to just 157mm last time around. And the wheelbase has been stretched to the benefit of rear-passenger room – a bugbear of the old GLA. That's progress.

This might be a personal thing but to me nearly all Porsches look better from the back than the front.

It's the wide stance and powerful haunches, the hunkered down suction-capped-to-the-road look that does it for me and the Cayenne Turbo GT, despite being an SUV, passes this important Porsche checklist item.

The GT aero kit only serves to make this SUV look more of a beast, and the gold-bronze looking satin Neodyne wheels are a Porsche theme that I've not always been a fan of, but I get the historic connection.

If only the Turbo GT could look a little less like other Cayennes from the front. This is the king of the SUV range and despite the apron and bumper already being exclusive to this model, there should be more.

Vents in the wheel arches, carbon bonnet with nostrils GT3-style perhaps? Or is that going too far? If you do want something more lairy then there's always the Urus.

The Cayenne Turbo GT's cabin is stunning in its plushness and modern surprises such as the passenger display, the hoodless instrument digital cluster, the lashings of Race-Tex upholstery everywhere. It's perfectly Porsche. High-performance meets high-end.

It's also highly practical. Let's talk about that.

Compared to before, the 2021 GLA is some 122mm taller, so ushers in a higher hip point for loftier seating – reducing that jumped-up hatch feel. Headroom improves obviously, as does rear legroom, a corollary of a 30mm wheelbase stretch (to 2729mm).

Wide apertures also make entry into and out of the German-built GLA child's play, though the solid heft of their doors is serious business at this end of the segment, very satisfyingly Teutonic and totally on-brand. This is something you won’t enjoy in a Subaru XV.

Then you s-c-r-a-p-e the underside of the front doors on the pavement literally every time you swing it to get out, and wonder whether Mercedes engineers have ever been to Australia. This fail drove us spare. Heaven help the GLAs in towns and cities with bluestone sidewalks. Maybe all that extra AMG packaging is the culprit.

Still, most of the other basics are spot-on and can’t really be faulted; cosy yet spacious for four adults – especially up front, ample vision, an excellent driving position aided by heaps of seat and steering wheel adjustability, cosseting front sports buckets that you just sink into, torrents of ventilation from those delectable turbine vents and stacks of storage. Collectively they make the GLA a welcoming, opulent place to travel in. Only the hapless fifth occupant squished between the outboard rear-seat passengers might think otherwise. But nobody buys this Benz for carting people around. That's the GLB's job.

Several years ago, Daimler poached a senior Audi designer and since then Mercedes’ dashboards have morphed into a multi-coloured multimedia diorama of touchscreen technology that threatens to completely take over the universe. Choose the right combination of colours and lighting and it's like your very own White Night on wheels. Starting with 2018’s A-Class, the striking, spangly MBUX system that underpins all this has come to be widely admired and imitated. For aesthetics anyway, with its vivid hues, panoramic displays and simple, tiled applications, it’s been a real trip.

Anyway, back to reality. From a tactility and functionality point of view, there’s still work to be done.

Access to the multimedia (including our GLA's banging optional audio system) and car settings areas is possible via a mildly fiddly finger-pad arrangement down forward in the centre console, or smaller yet much more annoying thumb sensor tabs on the wheel spokes. These are not easy to modulate on the move. Additionally, their menus can be confusing to navigate through and sometimes counterintuitive in operation. Mercedes obviously realises this as a quick-guide pamphlet is provided on old-fashioned cardboard paper. How quaint.

Eventually all areas can be mastered over time, but the functionality is complicated and may overwhelm the not-so-tech savvy. Additionally, the ‘Hey, Mercedes!’ voice control is impressive for getting MBUX to perform basic multimedia and vehicle settings-related changes, but it too-often erratic, unreliable and ultimately frustrating for more complicated commands. Perhaps elocution lessons on behalf of the operator may help.

But not as much as the profound disappointment we endure from the cheapness of some of the materials, the wincing cellophane-like sounds when pressing on some of the surfaces such as the door cards, or that emanate after a particularly bumpy section of bad roads. Sheeny reflections and hard textures in a car optioned with extras that total up to nearly $82,500 just don’t cut it.  

At least in this latest-gen GLA, the rear seat area seems much improved over the previous models, with more space, comfy and supportive seating (remember ours featured the $607 sliding function that ought to be standard) and a reclining backrest. All amenities are present, with deep pockets, fresh air from twin vent outlets, reading lights and thoughtfully placed armrests – but, again, the latter’s extendable cupholders feel brittle and cheap.

Further back, the 435-litre cargo area is sufficiently sized and practical for smaller family use (at last), aided by a 40/20/40 backrest fold and that slide-able cushion to extend capacity further. There is no spare wheel, but a tyre inflation kit is fitted in lieu.

Overall, then, better than before, with that fundamental rock-solid heft, luxurious aura and alluring premium-car aroma. The dazzling MBUX screen-related visuals, too, are endlessly entertaining to explore when the vehicle is not moving, but the GLA’s cabin is still not quite up to Mercedes’ reputation for exacting over-engineered excellence.

Or even to the standards of some mainstream alternatives.

The Porsche Cayenne Turbo GT only makes one compromise on practicality and that's the removal of the middle seat in the back, which, with just two kids isn't used all the time but on average we might need it once a week for school mates and cousins.

Instead of a middle seat there is a shallow tray, which will fit a phone or in our case leaves and rocks found at the park.

So, yes, the Turbo GT is a four-seater only, but this is a spacious, large SUV with good head and legroom, wide-opening doors for easy entry and exit, and air suspension which can raise and lower the height for easy access.

Storage is excellent with enormous door pockets in the front and back and there are four cupholders.

There's a wireless phone charger in the front and two USB-C ports as well, plus two USB-C sockets in the back.

Four-zone climate control means the kids in the back can set their own temperatures. They also have heated seats.

I was disappointed to see there aren't sunshades for the rear windows - pretty vital in Australia where it feels like we're only about 50 metres away from the sun.

The Turbo GT's 576-litre boot just managed to fit our pram and a week's shopping, which is our minimum standard for living. Any more space is a bonus.

The Turbo GT is the king of Cayennes, so it shouldn't surprise anybody that it's also the most expensive with its list price of $364,700.

Lamborghini's Urus lists for $409,744  and is the Cayenne Turbo GT's not-so-subtle Italian cousin, sharing the same platform and engine.

Both are in my mind the best performance SUVs on the planet. It just depends how conspicuous you want to be.

Then there's Bentley's V8 Bentayga which isn't blessed with the Porsche's good looks but would still be all over the Cayenne if the two happened to meet at a race track.

So, why is the GT Turbo the king of the Cayennes? What makes it better? For all the reasons you'd think - it's the fastest, most powerful, most luxurious and most equipped Cayenne in the range.

We'll get into mind-bending engine and performance specs soon, but first let me take you through the standard features on a car that's anything but standard.

Coming standard and exclusively to the Turbo GT are 22-inch 'GT Design' wheels in satin 'Neodyne' with full-colour Porsche centre caps, an active rear spoiler, Turbo GT front apron, dual titanium exhaust, rear apron with diffuser, 'SportDesign' side skirts, wheel arch extensions, a lightweight carbon roof and tinted LED HD-matrix headlights.

Inside, and also exclusive to this grade, is the 'GT Interior Package' with 'Race-Tex' upholstery throughout with 'Deep Sea Blue' stitching on the front seats and centre console and the armrests and dashboard.

There's also the 'Carbon Interior Package' which includes dashboard and door trim elements.

Race-Tex trim is applied to the 'GT Sports' steering wheel, roof lining and gearshift, too.

The adaptive active air suspension, which can lower the car by 15mm, is standard and only available on the Turbo GT, too.

The soft-close doors are standard (a cost option on lower grades), as are the stainless steel pedal covers.

The rest of the features are also found on lower grades and include the 12.65-inch digital instrument cluster, head-up display, proximity unlocking, 12.3-inch multimedia touchscreen with sat nav, wireless Apple CarPlay and Android Auto, digital radio, a 10-speaker Bose sound system, heated front seats, rear privacy glass and an auto tailgate.

Four-zone climate control is standard on the GT Turbo, too, and so are heated rear seats.

Our car had several options fitted such as the front passenger display ($2860) and the Deep Sea Blue Accent Package.

The passenger display is a crowd pleaser, but as a family car my kids felt like they were missing screens in the back seats, too. Well, in my day...

Mounted transversely, Mercedes’ M260 1991cc 2.0-litre four-cylinder petrol engine features a twin-cam, 16-valve design, a twin-scroll turbocharger and variable-valve timing, to help deliver 165kW of power at 5500rpm and 350Nm of torque at a low 1800rpm. With an impressive 97.2kW per tonne, it can hit 100km/h in 6.7 seconds, on the way to a 240km/h top speed.

All four wheels are driven by an eight-speed dual-clutch transmission (DCT), though most of the torque at lower speeds or during reduced throttle loads is delivered to the front wheels until extra traction is required out back. The gearbox is one of the very best of its type we’ve experienced – seamless, strong and largely lag-free.

As a middle-aged parent with two children, a Porsche that I don't have to crawl into and out of like a cubby house is a great thing.

What's even better is that this ‘easy access' Porsche is every bit as brutally powerful and fast as the quintessentially ‘pure' Porsche, the 911. Actually, it's more powerful and faster.

The Turbo GT's twin-turbo 4.0-litre V8 petrol engine makes 485kW and 850Nm with drive going through an eight-speed transmission to all four wheels.

In comparison, a Porsche 911 GT3 RS, arguably the most brutal and anti-social 911, has 386kW/485Nm.

I haven't made a mistake. Those are the real numbers. And it's only when you step on the accelerator in the Cayenne Turbo GT, and it feels like somebody's sat down on your chest, that you realise what a big deal this is.

That is such a colossal amount of oomph that this 2.2-tonne family SUV can accelerate from 0-100km/h in 3.3 seconds.

The 911 GT3 RS can do it in 3.2 and it has a roll cage and a fixed rear wing the size of a bedroom door.

And yes, we're now coming into a digital age where Teslas and other electric SUVs are quick, too, but can they go around corners like a Porsche Cayenne Turbo GT?

Do they have the same rumble and roar as a twin-turbo V8 that's terrifying and enticing at the same time.

The correct answer is, absolutely not.

Weighing in at 1668kg (kerb), and with a bluff nose and high ground clearance also not helping, we didn’t expect great fuel economy, particularly given how hard and fast the GLA 250’s performance bandwidth is. It’s tempting to just blast your way from point A to point B.

However, at the pump we averaged 9.8 litres per 100km, which isn’t too bad at all considering the available muscle. The official figure is 7.5L/100km, for a carbon dioxide emissions rating of 170 grams per kilometre. With a 51-litre fuel tank, the theoretical range is around 680km.

Note that the GLA 250 requires 95 RON premium unleaded petrol as a minimum.

Seriously? This is a 2.0-tonne twin-turbo petrol V8 with a 90-litre fuel tank. Even the Porsche specs sheet doesn't understand the question because in the column for fuel efficiency there are three letters - tbc.

My own testing saw me record 22.5 L/100km at the fuel pump, which means I enjoyed driving the car very much.

A little digging around reveals Porsche globally claims the Turbo GT will use 12.6L/100km, over a combination of open and urban roads.

You might not have as much fun as I did but easing back a little might get you closer to the 700km of range this more frugal consumption figure appears to offer.

While efficient it isn't, I'm not going to mark the Turbo GT too much here because compared to its petrol rivals the fuel consumption is what I'd expect from such a high-output heavy SUV.

A soaring 2.0-litre turbo engine application, this is a slick, stirring and robust performer that can also do efficiency as effortlessly as launch the GLA 250 4Matic towards the horizon. Let’s not mince our words. This is a fast and fiery mover.

Three drive modes – Eco, Comfort and Sport – provide a wide spectrum of acceleration and throttle responses, and all deliver precisely what you’d expect. Eco’s fine for pottering around town smoothly and serenely; Sport morphs into a searing and seamless speed demon; and the default Comfort sits somewhere in the middle as the best of both worlds. There really is no faulting Mercedes’ M260 masterpiece.

The DCT also happens to be one of the better dual clutch autos, avoiding the lag and clunkiness pitfalls usually associated with this sort of gearbox. It’s even comparatively smooth off the line on hills. Ours came with the optional handy set of manual-mode paddle shifters, adding a welcome level of interactivity autos tend to overlook. Too bad Mercedes persists with that fiddly column lever that is forever prone to knocking the car out of drive. Even after 15 years, it's still so annoying.

What all this means for the urban driver is strong acceleration for flitting in and out of traffic gaps, as well as incredibly instantaneous point-to-point responses for commanding manoeuvrability, thanks to ultra-eager steering and assisted by outstanding brakes.

With struts up front and a multi-link rear end as standard, the GLA 250’s chassis, too, is a transformative for what is essentially a high-riding hatchback – but only if your pockets are deep enough.

Fitted with that near-$3K AMG Exclusive Package that includes adaptive dampers, our Benz displayed a definite hot-hatch attitude that really would make it the darling of Golf GTI owners who’ve outgrown their rides but not their girl/boyracer desires. Superb handling and hunkered-down roadholding really do make this the driver’s premium compact crossover. You can pretty much point and shoot this Merc as you might a Golf R, and likewise in most weather conditions thanks to all that reassuring tenacious grip.

Plus, if you’re put off by the hard ride in Sport, the Individual mode allows the driver to engage the soft damper mode while the engine and steering retain the hardcore settings. It’s a win-win situation – as long as you can stretch to that AMG Exclusive pack. We strongly recommend it, given the balance between ultimate high-speed control and comfort.

However, while this is all good news for rural and country folk seeking hot crossover fun, back around town, poor urban road conditions can reveal a flaw in the chassis’ ability to properly smother bumps and ruts. It’s the small frequency stuff that seems to transmit through, never really settling down.

The result is a jittery ride, that may somewhat undermine the GLA’s upmarket sheen. There’s also a fair degree of road noise coming through. Perhaps sticking with the 19-inch alloys instead of those lovely 20-inch rims is the solution here.

Never have I met a car this powerful and superbly athletic that is as pleasurable to drive alone on great, fast roads as it is to pilot at 50km/h in the suburbs with a family on board.

It exceeds my understanding of engineering that something this large can move so quickly. That in an instant can turn and tip into a corner with such precision and effortlessness.

Yet it can switch seamlessly and happily to coping with speed bumps and potholes, delivering a ride so comfortable it'll send babies off to sleep. And it did.

The only issue, and this is such a tiny thing, is the dash-mounted gearshift, which means having to reach up and select Drive or Reverse or Park, which, when executing a three-point turn, is necessarily frustrating.

Still, I'm giving the Turbo GT a 10 out of 10 for driving under all conditions, and we didn't even go off-road, which of course you can do, as long as it's not too wild.

The Porsche Cayenne Turbo GT hasn't been locally crash tested and so doesn't have an ANCAP rating.

That's quite normal for super high-end cars. But, when this third-generation model first arrived in 2017 it was tested by ANCAP's European equivalent, Euro NCAP, and was awarded the maximum five stars.

There's AEB which operates at city, urban and highway speeds, and lane keeping assistance, and lane change assistance which is a form of blind-spot warning, and adaptive cruise control. You can option rear cross-traffic alert, as well.

A space saver spare wheel is under the boot floor.

Unlike many luxury brands that persist with a sub-par three-year warranty, Mercedes-Benz offers a five-year/unlimited kilometre warranty.

Intervals are every year or 25,000km, with a capped price service plan starting at $550 for the first year, $750 for the second year and $1250 for the third year, totalling $2550. Alternatively, buyers can also choose a Service Plan, starting at $2050 for the first three years (saving $500 from the normal capped-price service plan), $2950 for four years and $3500 for five years.

The Cayenne Turbo GT is covered by Porsche's three-year, unlimited kilometre warranty, which is lagging behind in terms of duration even compared to other luxury brands such as Mercedes-Benz, which offers five years.

Servicing is recommended annually or every 15,000km, although there isn't a capped price maintenance plan with final costs determined at the dealer level (in line with variable labour rates by state or territory).