Mercedes-Benz GLE400 vs Porsche Cayenne

What's the difference?

All told, the Mercedes-Benz GLE 2020 model is an improvement in many ways over its predecessor. It's safer, more high-tech, considerably more luxurious and practical inside, and offers better value, too.

But, in 300d guise at least, it's let down by a slightly underdone engine, and suspension that just doesn't do a good enough job on rougher roads. It's close, but not close enough to be best in class.

Maybe that'll be a different case for the higher-grade versions with the most high-tech engines and the tricky optional suspension... we'll have to wait and see.

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.

You can make your own mind up about the styling of the new GLE. It's certainly more aggressive than the model that came before it, and Benz claims that it's the most aerodynamic SUV in its class.

The models on test were all fitted with the AMG styling pack and the bigger 21-inch multi-spoke wheels, and from some angles it's a striking car. I particularly like the way the rear-end treatment has worked for the GLE: the triangulated tail-lights, the lower bumper and the rear glass all work together well.

In profile, the GLE is quite challenging to look at. The rounded window-line is a bit awkward, and somehow the wheels just don't fit with the bulky guards (though I do like the way the AMG 21s poke out a bit at the back).

The front sees the diamond-style treatment to the grille for the AMG Line versions, but there's a lot of black plastic on the bumper, and the headlight shape gives it a bit of a droopy-eyed look. Is it just me, or is it a bit of a Bassett Hound? 

It is a bigger car than before - 111mm longer (now 4930mm - and on an 80mm longer wheelbase, now 2995mm), and it's 15mm wider but 31mm lower - and it looks more substantial as a result. I'm just not sure it's pulling off its bulk as well as it could.

So the outside is pretty, er, interesting. We had comments from passersby to that effect, too, and in our comparison test it was the consensus of our team of experienced testers that the GLE had some challenging exterior design elements.

But inside is where the best bits hide, with a lot of luxury finishes, materials and technology giving the GLE some wow factor that its exterior design arguably misses out on.

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.

The cabin presentation and pragmatism is excellent in the new-generation GLE. There was an existing version on site for us to compare, and to say it's like night-and-day would be generous to the old model.

A lot of that comes down to the MBUX twin 12.3-inch screens on top of the dash - one for all the driver instrumentation and controls, and the other for sat nav, media, car controls and other settings. They look great, and there are multiple ways to control them: the steering wheel controls, the touch pad between the front seats, the screen in the middle is touch-capacitive, and there's the much-bragged-about “Hey Mercedes” voice control system.

But it's more than just the screens: the finishes and materials used in the GLE are exceptional. The plastics are excellent, the brushed aluminium treatment that runs the width of the dash with ambient lighting, the surrounds on the vents (oh, so many vents!) - it all works so well together. But the open-pore wood finish is my favourite element, adding a touch of ruggedness that's also plush and luxurious.

The test cars all had the high-end leather treatment and optional bolster-heavy seats, and they're okay, but a little fiddly to adjust. I guess that's the beauty of driver profiles - the car will remember your favourite settings and make the adjustments as you get in or out by detecting the key.

There's also excellent storage throughout - the door pockets in all four doors are huge, there are cupholders front and rear, and loose item storage is decent, too. Plus there are heaps of USB-C (fast charging) ports up front and in the back.

Speaking of the back, the cars at launch all had the seven-seat package, which might appeal to you, or not. It's more than just a couple of seats in the back row, because it includes electric seat adjustment for the second row, with slide and recline functions allowing you to prioritise second- or third-row space.

The space in the second-row with the seats set as far back as they can go is excellent. There's heaps of room for someone my height (182cm) to sit behind a similar sized driver with ample knee room, headroom and shoulder room. You'll be able to fit three adults across the back, or if you have kids, there are three top-tether points and outboard ISOFIX child-seat anchors, too. No child seat restraints in the third row, though.

Whether you choose the five-seat or seven-seat option, the boot space remains the same at 825 litres with five seats in play. All models have an electric tailgate, too.

And if you're curious about the third row, it should be fine for anyone shorter than 175cm for shorter drives. It's not super spacious back there, and should be considered a 5+2 option. Really need a seven-seat Merc? You could get a GLS if you can afford it, or go for a V-Class luxury van. Go on. Do it!

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...

Powering the Mercedes-Benz GLE is a selection of engines, with petrol and diesel offered.

The entry-level power plant is the 300d, which uses a 2.0-litre four-cylinder turbo-diesel engine with 180kW of power (at 4200rpm) and 500Nm of torque (from 1600-2400rpm). It has a nine-speed automatic transmission and all-wheel drive as standard.

The range-topping diesel is a thumper. It's the 400d, which runs a 2.9-litre turbo-diesel six-cylinder with 243kW of power (at 4000rpm) and 700Nm of torque (from 1200-3000rpm). It also has a nine-speed auto and AWD standard.

The sole petrol model at launch is the 450, which employs a twin-turbocharged 3.0-litre in-line six-cylinder engine with 270kW of power (at 5500rpm) and 500Nm (at 1600-4500rpm). It uses a nine-speed automatic transmission with AWD, but this version is the only one with mild-hybrid tech, using 48-volt EQ Boost tech to help add 16kW and 250Nm for short stints of added performance (0-100km/h in just 5.7 seconds, apparently), and allowing the engine to shut off under light throttle or lift-off situations.

If you plan to tow, there's a factory-fit tow pack available that allows 750kg unbraked and 3500kg braked towing across all grades. This pack is the one from the factory - remember that - and it costs $1900. If you instead fit one as an aftermarket fit, the figures are 750kg/2700kg respectively.

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.

Fuel consumption varies between the models, as you'd expect.

The 300d is the most frugal of the mix, with an official combined cycle fuel use claim of 6.9 litres per 100 kilometres. The 400d, with its bigger six-cylinder diesel, is said to use 7.7L/100km. The 450 petrol model has the highest claimed fuel use, at 9.1L/100km, and that's despite the fact it's the only version of this trio to bring electrification into the mix with the EQ Boost 48-volt mild hybrid system.

On test at the launch of the GLE we saw a displayed return of 9.4L/100km for the 300d model, but there was a fair bit of country road and highway driving in the mix.

All versions of the GLE are fitted with an 85-litre fuel tank.

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.

The launch drive was limited to the 300d variant, though I did get a chance to sample the version with air suspension, as well as the model with the standard steel suspension.

Now, before we get too nerdy, this is an important element for a luxury SUV. Ride comfort is arguably as vital as effortless power. And, sadly for the GLE, neither model sets any benchmarks for suspension control and comfort.

The steel-sprung model doesn't have adaptive suspension at all, meaning that it can be bouncy, wobbly, unsettled and stiff all at the same time. The country road I sampled it on showed that the standard suspension offered up a quite nervous experience, never feeling as settled as a luxury SUV really ought to.

The air suspension version is definitely better, but still not as good as a BMW X5, Audi Q7 or VW Touareg. It lacks the body control and comfort that a true luxury SUV ought to offer.

Now, that might matter to you, or it might not. You might think the look of the car - with 20s, 21s or 22s filling the guards - is more important than how it deals with lumps and bumps. But it's our job to tell you how the land lies, and the GLE simply can't match the better SUVs in this segment as a driver's tool.

There is another level of suspension which the CarsGuide team (myself included) hasn't yet had the chance to sample - the E-Active Body Control system, which includes curve-tilting so it can make the car feel level through corners, and a system that'll scan the road ahead to predict bumps and lumps and prime the suspension to deal with it. That system is $13,000... and, while I haven't sampled it yet, it's my hope that it makes all the difference to the GLE.

So, what about the other driving elements? Well the steering is light and accurate, and decently responsive at low speeds or highway pace, and you're never left guessing as to what'll happen.

The engine, too, is decent - a 2.0-litre with 180kW and 500Nm is nothing to be sneezed at - but in a vehicle this large, with a kerb weight of 2165kg, and with a nine-speed automatic taking care of forward progress, it can be a busy engine.

That's because the transmission will shuffle between ratios when you encounter a hill as it doesn't quite have the grunt to simply stick in a gear and tug you along. It's not that big of a deal, and the transmission is smooth enough and pretty hard to catch out, but it is a little less effortless than a six-cylinder would no doubt be.

All in all, I was left wanting more from the drive experience. Maybe the higher-grade models with the highest-grade suspension will prove a better flag waver for the new-generation GLE.

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.

Mercedes-Benz stands by its three-year/unlimited kilometre warranty plan, stating at the launch it has no plans to extend it to match what most of the mainstream brands now offer (five years). But it's not alone in the luxury segment in that regard.

The big point the company's local reps made was that they're trying to lower the cost of ownership for customers through servicing packages. You can pre-pay them, or you can pay as you go (PAYG).

The GLE requires maintenance every 12 months or 25,000km. The pre-pay option is $2700 for the first three years/75,000km of maintenance or, if you decide to PAYG, the costs are $850, $1200 and $1250 (totalling $3300 over the same period). It makes sense to pre-pay then, and you can bundle the cost into your finance, too, so you'll notice it less.

There is three years roadside assist included at no cost if you buy the car brand new, as it coincides with the warranty period.

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).