Audi Q8 vs Mercedes-Benz Gls450

What's the difference?

The updated Audi Q8 60 TFSIe quattro S line still looks good inside and out. It fits a family comfortably without feeling too big and there’s enough here to satisfy those who like the luxury features. 

It's price tag will hurt it but the improved power outputs and driving range is a big plus and makes the plug-in hybrid powertrain make more sense.

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.

When it comes to style, the Q8 60 TFSIe quattro S line has it in spades. Featuring a design that looks athletic with its long lines and wide stance, you'll always be proud to hop into it.

Red calipers now come standard and they look awesome on the optioned 22-inch alloys. The update sees a redesigned front with new grille and reshaped matrix LED headlights and a 2D badge design.

While SUV coupes aren’t usually my jam, the Q8 manages to tick the 'sexy' box.

The interior is honestly the same and only die-hard fans will notice the new menu screens on the multimedia system. The cabin is a fine example of what a luxury SUV should look like because its polished, well-built and sumptuous but it has the classic Audi edge, so there is still a sporty vibe going on.

The panoramic sunroof adds some airiness to the otherwise dark cabin and the Valcona leather upholstery is liberally splashed about, so most of what you touch feels premium and soft.

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.

The cabin offers plenty of space for passengers and you never feel like you're jostling for elbow room unless there's three adults across the rear seat. Comfort is high with ergonomic seating up front with plenty of adjustment and functions. The rear seat has long bases and the seat backs can recline.

Individual storage leaves a little to be desired for the class and the glove box shoulders most of the burden up front as the middle console is really just a shallow shelf large enough for a wireless charging pad and keys or a chapstick.

Each row gets a couple of cupholders and drink holders, and the rear map pockets round out back-seat storage.

Because of the PHEV powertrain, the 60 TFSIe quattro S line has the smallest boot capacity in the line-up at 505L but this is still more than enough for a decent road trip or grocery haul.

The wide boot aperture, level loading area and powered tailgate add some convenience, as does the 40/20/40 split fold on the rear seats.

Access for each row is solid with wide door openings, low seat positions and 205mm ground clearance. Although, the doors have to been slammed shut for them to close properly and this annoyed everyone in the family. You can spring for a soft-close door feature for $1500 and, honestly, it would be worth it.

The 10.1-inch touchscreen multimedia system is logically laid out and the graphics look great. It has haptic feedback which my husband didn’t love as it made it hard to select things on a bumpy road. You also get built-in sat nav, wireless Apple CarPlay and Android Auto. Other than the occasional lag with the CarPlay connecting upon start up, it's all simple enough to use.

Charging options are good with two USB-C ports in each row and the front also gets a wireless charging pad. The big 12.3-inch digital instrument cluster looks great but it can be annoying to find information on it or personalise it.

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.

Our Polar White test vehicle, which is the base grade in the three-tiered GLS range, comes standard with a 3.0-litre inline six-cylinder turbocharged diesel engine with 48V mild hybrid technology, nine-speed automatic transmission, permanent all-wheel drive and active air suspension for a list price of $189,100.

This pricing is higher than comparative entry-level grades offered by the two marques which dominate sales leadership in this segment, comprising the BMW X7 xDrive40d M Sport ($179,500) and Lexus LX500d AWD ($158,700).

The GLS450d’s standard features include 22-inch AMG alloy wheels with Continental 325/40 R22 tyres and a collapsible spare, ‘AMG Line’ body styling enhancements, aluminium-look illuminated side-steps with non-slip rubber studs, multi-beam LED headlights and more.

Step inside the keyless interior and you’ll find ‘Hey Mercedes’ voice activation, fingerprint scanner (which memorises individual comfort settings for up to seven users), panoramic sunroof, heat-insulating dark-tinted rear privacy glass and the ‘Premium Plus Package’ that includes heating/cooling for the front seats, heated rear seats, head-up display, separate front/rear climate control zones, heated cupholders and more.

There’s also a concert hall-like Burmester surround sound system controlled by a central touchscreen with digital radio and Apple CarPlay and Android Auto connectivity, plus wireless phone charging, multifunction Nappa leather sports steering wheel and USB ports front and rear.

Driver assistance includes the ‘Parking Package’ (360-degree camera, active parking assist and transparent bonnet), ‘Mirror Package’ (auto-dipping rear-view mirror and electric folding door mirrors with puddle lamp projection of the brand logo) and ‘Driver Assistance Package’ (blind-spot assist, exit warning, speed sign recognition, lane keeping etc) all included as standard equipment.

Of course, Mercedes-Benz offers numerous extra-cost options including a 3500kg towing package plus interior, exterior, suspension and wheel enhancements (including Nappa leather trim) for those who want their GLS with the lot, which can easily push the list price beyond $200K.

The Q8 60 TFSI e is AWD and has a 3.0-litre V6 turbo-petrol plug-in hybrid powertrain for a combined power output of 360kW and 700Nm of torque.

The power output has increased by 20kW with the mid-life refresh and that shaves 0.4 seconds off the 0-100km/h sprint time bringing it down to just 5.0 seconds. So it’s a quick and powerful SUV.

The powertrain is paired with an eight-speed automatic transmission which is mostly smooth and the switch between petrol and electric is fairly seamless.

As far as plug-in hybrids go, everything seems to work well here.

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.

The mid-life update sees a larger 25.9kWh lithium-ion battery which improves the electric driving range by 27km, bringing it up to 74km overall. This still falls short of its direct rivals but it’s an improvement for efficiency because it’s now more than enough range if you’re just doing the school runs and some errands around town.

The Q8 60 TFSIe has a Type 2 charging port and like most plug-in hybrids, lacks a CCS enhancement, so you have to make do with AC charging options with this one. On a 7.4kW AC charging system you can go from 0-100 per cent in three hours and 45 minutes but if you’re using just a standard house plug port, it will take a few hours more. It's best to leave it overnight.

Audi throws in three charging cables, including a 240-volt domestic charger but you have to pay extra for a wall-mounted box.

The official combined fuel cycle is a low 1.8L/100km and like all plug-ins the best efficiency will be achieved if you charge it often. After charging almost every day and doing a mix of open road and urban driving, my real-world usage has popped out at 7.7L/100km, which isn’t as good as I was hoping but it’s not terrible. I would expect the efficiency to drop on longer trips.

The Q8 likes to drink the good stuff and Audi recommends a minimum 95 RON unleaded petrol to be used for this grade.

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.

The Q8's athletic looks are matched by its on-road handling. The power has a hefty kick that’s effortlessly delivered once you’re up to speed. It did have a few confused moments when I had to accelerate quickly from a full stop - the lower gears didn’t immediately engage and I got a proper bunny hop but it was short lived and for the most part the powertrain delivers the goods.

The adaptive air suspension makes for a comfortable ride despite the massive wheels and you can comfortably cruise around town or the highway without much jostling.

Cabin noise is minimal around town but you get a low hum of road noise at higher speeds. Overall, it's still a refined cabin space to spend a lot of time in.

I do miss hearing some of the engine thrums though because even when the battery is depleted, you don’t get a lot of engine feedback. It certainly adds to the refinement but it loses some of the fun.

The higher driving position feels comfortable and visibility is quite good. Steering is responsive and feels sporty with lane changes but its 13.3m turning circle lets it down in car parks.

The 360-degree view camera system is clear and this has multiple parking sensors. In theory parking should be easy but again, until you get used to that bigger turning circle it can feel clumsy in smaller spaces.

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.

The GLS does not have an ANCAP rating as it’s yet to be tested, but comes standard with a suite of passive and active safety features including nine airbags, auto emergency braking (AEB) with pedestrian detection and junction assist, blind-spot monitoring, traffic sign recognition, head-up display, rear cross-traffic alert, lane-keeping, adaptive cruise control with ‘distance assist’ (autonomously brakes/accelerates in heavy traffic), front/rear parking sensors, 360-degree camera and more.

There’s also two ISOFIX and three top-tether child seat anchorages in the second row, plus two more of each in the third.

Audi offers the Q8 60 TFSIe with a five-year/unlimited kilometre warranty and the battery is covered by an eight-year/160,000km warranty which are all pretty standard terms compared to its rivals.

There is a standard five-year servicing package that costs $3570 and servicing intervals are spaced at every 12 months or 15,000km, whichever occurs first. However, if you purchase the Audi Advantage Package you add a further two years of coverage to the warranty, roadside assistance and servicing, which is pretty good for the class.

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.