Mercedes-Benz Gls450 vs Audi Sq8 E-Tron

What's the difference?

The GLS450d impresses as an entry-level grade, as it’s a more family-friendly allrounder than the specialised AMG and Maybach variants. Its combination of a torque-rich diesel 48V hybrid drivetrain, air-cushioned suspension and plush interior are as well suited to luxury urban travel as they are to grand touring, where its heavy towing and generous load-carrying capabilities can shine. Whether it’s worth around $200K drive-away, only those who shop at the top end of town can decide.

There’s not doubt large, luxury SUVs like the SQ8 have a lot to gain from electrification in terms of refinement, performance and running costs. The flip-side is the extra mass of the batteries and other electrical gear but, in this case at least, there might be a silver lining there in the way the hulking SUV manages to force the air suspension into agreeable submission.

For our money, the station-wagon variant is the one to buy. It’s cheaper to begin with and with its greater luggage capacity, it simply makes more sense. Which is not to say the Sportback version is compromised in luxury, safety or performance terms, but if practicality doesn’t figure highly in any purchasing decision involving an SUV, then we sense a great disturbance in the force.

Regardless of what’s powering the SQ8, the driving experience is vintage Audi and that’s a good thing, and even that massive kerb mass can’t blunt the sort of chassis dynamics and feedback we’ve come to expect from the brand.

Some buyers will possibly baulk at the projected range and the Audi’s appetite for electrons, but when lined up side-by-side with its major competition, the SQ8 is every chance to emerge as the one to buy. We’ll need a proper comparison for that, of course, but the Audi should be on any short-list of big, deluxe, electric SUVs.

Note: CarsGuide attended this event as a guest of the manufacturer, with accommodation and meals provided.

This is an imposing vehicle in extravagant S-Class tradition, riding on an expansive 3135mm wheelbase and stretching more than 5.2 metres (5215mm) long and more than 2.0 metres (2030mm) wide with a turning circle that's nudging 13 metres.

However, it’s just under 1.8 metres (1798mm) tall, so there’s no clearance issues when accessing multi-storey carparks. And with its side-steps (or ‘running boards’ in nostalgic Benz speak) most adults can step rather than climb aboard, although passengers of shorter stature during our test noted that assist handles on the A and B pillars would be handy.

Central to its sophisticated chassis design is adaptive air suspension, which uses a pneumatic or ‘airbag’ form of springing with adaptive damping to continuously optimise ride comfort and handling response according to road conditions and driving dynamics (see Driving).

The GLS’s styling is clean and uncluttered with tasteful restraint evident in its chrome and satin-chrome highlights, yet it projects a majestic quality with its prominent four-louvre grille and elegantly spoked alloy wheels.

The spacious and sumptuous seven-seat interior is visually pleasing and practical, with a subtle blend of surface treatments, contrasting tones, lots of soft-touch surfaces and exposed stitching. This is combined (thankfully) with physical dials, switches and ‘piano key’ buttons to control numerous interior functions, in preference to distracting touchscreen prompts.

Stylistically, the big news is that the SQ8 is the second model to take up Audi’s latest exterior design language. That includes the two-dimensional Audi grille logo as well as a 'singleframe' (Audi’s own word) light bar that links the matrix headlights.

The SQ8 also gets Audi’s Sport Package as part of the price of admission, and that includes black roof rails and other touches.

Of more technical interest is the way the front of the car has been designed to aid air flow around the front wheels. Controllable flaps in the front fascia as well as underbody winglets keep the air flowing around the wheels without contributing to excess aerodynamic drag at speed.

In an engineering sense, the big news is the adoption of a three-motor layout. While some manufacturers are yet to see the value in this, having a motor on each of the rear wheels means there’s no longer a need for a rear differential.

Although it has a hefty 2655kg kerb weight, our test vehicle’s 3420kg GVM rating provides a useful 765kg of load capacity, which should comfortably absorb the combined weight of up to seven occupants and light luggage. Or with the third row of seating folded, five occupants and heavier luggage.

It’s also rated to tow up to 3500kg of braked trailer and with its sizeable 6920kg GCM (or how much weight it can legally carry and tow at the same time) it can carry its maximum load while towing its maximum trailer weight.

So, that’s commendable practicality, given it would be well suited to owners that need to tow large caravans, boat trailers, horse floats etc in style without having to compromise much (if at all) on either passenger numbers or luggage capacity.

Driver and front passenger space and comfort is exceptional, as you’d expect. Storage includes a large glovebox plus a bottle holder and bin in each door. The front of the centre console has two USB-C ports, wireless phone charging and heated cupholders, while the rear of the console has a large storage box with a third USB-C port and padded lid that doubles as a comfy elbow rest.

Even tall passengers in the second row of seating enjoy spacious comfort, given I’m 186cm and with the driver’s seat set in my position I have ample knee clearance, foot room and head space.

However, the central passenger must contend with a transmission tunnel in the floor and shoulder room would be squeezy for three large adults, which is okay for short trips but a maximum of two would be ideal for longer journeys.

The rear of the centre console also treats second-row passengers to a pair of USB-C ports, adjustable air-vents and a control panel that allows independent climate adjustment.

There’s also a large bin/bottle holder in each door plus storage nets on each front seat backrest. The centre seat backrest folds flat to allow long items (skis etc) to slot between the outer backrests. And it also serves as a fold-down armrest, containing two cupholders and a lidded slimline compartment that’s ideal for hidden phone storage.

The third row is uncommonly spacious, even for tall people, with padded armrests on each side containing cup holders and twin USB-C ports.

The carpeted rear luggage area has four load-anchorage points, a first aid kit and 12v socket. With the third-row seats upright it offers 355 litres of load volume, which increases to 1350 litres with the third row folded and 2400 litres (or 2.4 cubic metres) with both the second and third rows folded.

There’s absolutely no question Audi knows a thing or two about cabin layouts and ergonomics. Like other contemporary Audis, this one features the fully customisable Virtual Cockpit with a huge range of possible displays and layouts. And again, as usual, it all works seamlessly and efficiently.

The head-up display is amazingly clear and the twin touchscreens divide the car’s tasks logically. Yes, there’s a lot going on, but compare the way the Audi applies logic to the menu strategy to the scatter-gun approach of many others, and you can see that plenty of thought has gone into this stuff.

Also, it goes without saying, of course, that there are multiple charging points as well as plenty of connectivity with good wireless connections available. That includes wireless phone changing.

The front seats are sporty but not too firm, even if they do give you a bit of a squeeze thanks to high bolsters and lots of contouring. The rear seat is likewise firm initially and is really best for two backsides thanks to the sculpting of the rear bench.

That said, it will accept a centre passenger, but that seat will be the last one occupied. Rear legroom – important in a car like this - is good, there’s enough room for your feet under the front seats and headroom, even in the allegedly racier looking Sportback, is ample if not huge.

The panoramic sunroof means there’s plenty of light to counter the dark interior colours, and the only real surprise is the amount of hard plastic on the upper part of the door trims, just below the glass. Given the acres of much plusher trim farther down the door, this seems a bit odd.

The other comment we’d make is that the SUV body simply makes more sense in terms of load carrying (569 litres plays 528) and makes more of the SUV’s claim to practicality.

The Sportback is also a bit of an acquired taste and while it’s not the first SUV-coupe mash-up we’ve seen, to many eyes, the combination never looks right. Coupe on stilts? Surely, not for everyone.

On that subject of practicality, the SQ8 bucks the trend in EVs by being able to tow up to 1800kg with a braked trailer. The factory towing pack is a $2180 option.

None of the Q8 variants are what you’d call remotely spartan, and even the entry-level Q8 50 gets air suspension, Audi’s 'Virtual Cockpit', 20-inch alloy wheels, LED headlights, ambient interior lighting, dual-zone climate control, driver’s seat memory function, a head-up display, digital radio and a 360-degree camera.

The Q8 55 builds on that with the Sportback body (which is not available on the 50 variant) an extra 50kW of power from its twin electric motors, 21-inch alloy wheels, sports front seats and four-zone climate-control. There’s also an electrically adjustable steering column (the 50 has manual adjustment).

What makes the SQ8 the flagship car, of course, is not just more equipment (though there is plenty of that) but rather the optimised driveline with its three electric motors and 370kW output.

Beyond that, you also get a panoramic sunroof, 22-inch alloys, matrix LED headlights, heated front seats and a Bang & Olufsen premium sound system with no less than 16 speakers including 3D loud-speakers.

And because choice equals luxury, the SQ8 can be had in either of the Q8’s body styles; the station-wagon SUV or the Sportback. Neither of which run to a third row of seats.

Option packs include the 22kW charger option at $6900 and the 'Sensory Pack' which gets you headlights capable of branded projections on to your garage wall, e-tron branded puddle lights, powered, soft-close doors, heated rear-outer seats, an interior ioniser and 'fragrancer', extra dashboard leather and manual rear-window sun-shades. Yours for an extra $9600.

And if the SQ8 doesn’t look menacing enough, there’s a black exterior package at $2300 that, um, adds extra blackness.

The one option you need to think about carefully is the virtual mirror package which, at $3500, replaces the conventional mirrors with cameras that show what’s behind on panels in the top corner of the front door trims. It takes a bit of acclimatisation and revision of muscle-memory and is definitely not for everybody.

The price hike over the $140,600 entry level car is a hefty $33,000 for the SUV variant ($173,600) and a neat 40-grand for the Sportback ($180,600).

The GLS450d comes standard with a 3.0-litre turbocharged inline six-cylinder diesel producing 270kW of power at 4000rpm and 750Nm of torque between 1350-2800rpm.

This is paired with a 48V mild-hybrid system comprising a 48-volt battery (charged by regenerative braking) and an integrated starter-generator which provides both seamless engine stop-start and up to 15kW/200Nm of extra power and torque during acceleration.

A nine-speed torque converter automatic provides the choice of manual shifting using the steering wheel-mounted paddles, along with several selectable drive modes.

The active all-wheel-drive system continuously adjusts the engine’s torque delivery between front and rear axles (and individual wheels as needed) to maintain optimum traction and handling.

While many electric all-wheel-drive vehicles use a motor on each axle, the Audi electric 'Quattro' system here arguably goes one better with a total of three motors.

The front axle features the traditional single motor while the rear axle has two; effectively a motor on each rear wheel.

When they all chime in, they bestow the e-tron with a maximum of 370kW of power and an astonishing 973Nm of torque; more than enough to get the 2.6-tonne e-tron moving.

Enough, in fact to get the car from rest to 100km/h in a claimed 4.5 seconds and on to an electronically limited top speed of 210km/h.

A single-speed reduction transmission is fitted and drive is constantly sent to all four wheels via an electric version of Audi’s famed Quattro all-wheel-drive layout.

Suspension is by adaptive air springs and there’s adjustable (via the steering wheel paddles) regenerative braking.

Mercedes-Benz claims official combined consumption of 7.8L/100km and the dash display was showing 9.0 when we stopped to refuel at the completion of our 368km test, which included the usual mix of suburban, city and highway driving with up to five passengers at times and light luggage.

Our own figure, calculated from fuel bowser and tripmeter readings, was close at 9.5 which is outstanding sub-10L/100km economy for such a substantial vehicle in mostly metropolitan use. Therefore, based on our own consumption figure, you could expect a real-world driving range of around 950km from its 90-litre diesel tank.

Moving this much weight at such velocities and for such distances requires a big battery. In fact, Audi claims the SQ8’s battery, at 114kWh is the biggest in the business.

But, again, it needs to be, especially with the claimed energy consumption of a hefty 28.8kWh per 100km for the SUV version and 28.0kWh per 100km for the slightly slipperier Sportback.

That gives a theoretical range of 417km for the SUV and 430 for the Sportback, both of which are numbers some potential buyers won’t consider sufficient.

But those same people should consider the fact that in a mix of winding country roads and some freeway running, we were able to beat those consumption claims, recording closer to 26 or 27kWh per 100km which, if nothing else, suggests the published range figures might be somewhat closer to reality than the EV (or any other segment of the car industry) market typically gets.

The standard charger runs at 11kW but on a 10-amp household socket, home charging will be limited to 7.2kW, although an optional 22kW charger ($6900) is also available from Audi.

The DC charging is the highlight, however, and the SQ8 can cope with charging speeds of up to 170kWh, meaning it can theoretically get from 10 per cent to 80 per cent charged in about 31 minutes on a commercial charging station with enough grunt.

It’s an enjoyable vehicle to drive, with multiple power adjustments for the seat and steering wheel combined with a large left footrest which provide supreme driver comfort and support.

The powerful and responsive turbocharged six-cylinder diesel and nine-speed auto are well suited to this application. The engine’s ample torque provides spirited acceleration from standing starts, taking only six seconds to reach triple-digit speeds.

This drivetrain would be well suited to heavy towing duties, given the 48V mild-hybrid system can contribute an extra 200Nm (in addition to the engine’s 750Nm), which raises the total theoretical torque output to almost 1000Nm.

The active air suspension provides a wonderfully cushioned ride that floats over bumpy roads, while maintaining excellent handling response and surprising agility. These commendable chassis dynamics, combined with the powerful and responsive drivetrain, makes the vehicle feel smaller and lighter than its dimensions and kerb weight would suggest.

Overall, it’s difficult to fault from a driver’s perspective, with the only exception being the voice activation function. This is often triggered by words or phrases other than ‘Hey Mercedes’ resulting in regular interruption of conversations. This needs some fine tuning.

Almost a thousand Newton-metres (not to mention 370kW) infers some pretty serious performance and so it is.

When you press down on the throttle pedal, there’s an instant and somewhat furious response from the driveline. And just as the Audi’s touchscreens have been calibrated to respond on a human scale, so too have the major driving controls.

That said, while there’s more acceleration on tap than most drivers will ever have experienced, the SQ8 doesn’t move forward with quite the irresistible force the bald numbers might suggest.

And that’s purely down to the thing weighing the wrong side of 2.6 tonnes. Sure, Audi claims 4.5 seconds and that seems fairly believable, but it’s not quite as ballistic as some other current EVs.

Still, that’s hardly its mission in life, anyway. Top speed, in the interests of thermal management, has been limited to an entirely understandable – not to mention adequate - 210km/h.

But one thing all that kerb mass has (arguably) done is make the suspension work properly. Speaking purely personally, until I’d sampled the SQ8 over a variety of bitumen joins, potholes of all sizes and even clattering level-crossings, I was yet to drive a passenger car on air suspension that worked as well as the brochure claimed.

Historically, air suspension has been okay on smooth roads and even sometimes bigger lumps and bumps. But it usually fell short of expectations on small amplitude, high frequency stuff that made the suspension judder and stutter. Not this Audi.

Even on the 'Dynamic' setting, the ride never falls beyond plush although you will notice a little more stiffness being dialled into it by the computer.

The best advice is to leave it in the 'Comfort' setting where there’s still lots of roll and pitch control, yet an even higher degree of suppleness that fundamentally refuses to be beaten by a lack of post-Covid road maintenance. And this from a car that rides on 22-inch wheels and tyres.

Perhaps compressed air doesn’t scale in a linear manner, making the addition of a couple of tonnes of sprung mass a positive, rather than a negative.

The other thing Audi has done well to maintain is that almost indefinable corporate steering response.

It’s kind of muted this time around in terms of its ability to talk to you, but there’s still an over-arching Audi-ness to it with an instant pointiness without the frenetic feel often associated with a quick ratio and sticky tyres.

Like any modern, high-end SUV, the Audi is dripping with safety gear, both passive and the latest active driver aids.

Autonomous Emergency Braking is included, of course, but goes a bit further with pedestrian and cyclist detection. There’s also adaptive cruise-control with a speed limiter and the Audi offers assistance rather than just a passive warning with traffic-jam assist, collision avoidance assist, turn assist, exit assist, intersection assist, rear-cross traffic assist and lane-change warning and assist.

There are also front and rear parking sensors combined with a 360-degree camera system which includes a kerb view function for tight parking spots.

Given the bulk of the e-tron, that might be a pretty handy addition. A tyre-pressure monitoring system is also a great standard feature.

The SQ8 hasn’t been locally crash-tested but has scored a maximum five stars in European testing.

What’s missing? Probably only a central airbag to prevent front-seat head clashes in the case of a side impact.

The GLS comes with a five-years/unlimited km warranty (better than BMW and Lexus) and five years of roadside assistance. Scheduled servicing is every 12 months/25,000km whichever occurs first.

Mercedes-Benz offers capped-price pre-paid servicing packages with three, four or five-year terms. For example, the total upfront cost of the minimum three-year term is $4090, or an average of $1363 per service.

Audi’s factory warranty is a good, but no longer remarkable five-year/unlimited warranty on most of the SQ8.

The exception is the battery which is covered by a six-year/160,000km warranty. Audi will also come to your home and connect the standard 10-amp charger and there’s an Origin Energy green power offer that comes with it.

Charging is taken care of for the first six years with a Chargefox subscription as well as Audi Connect. You’ll also get six years of free roadside assistance and the first six years of standard servicing are also included.

The SQ8 also makes good on the EV promise of less maintenance with service intervals every two years or 30,000km, whichever comes first.