Mercedes-Benz Gls450 vs Bentley Flying Spur

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.

The Bentley Flying Spur Speed is a whole lot of car, for a whole lot of money. Sure, I’d rather have a Ferrari or a Porsche with similar power (and the Panamera shares the same V8 and hybrid set up), but then if you’re in the market for a Bentley like this you already have a garage full of other options. And I can see why you’d add one of these to your collection. Because you can.

Note: CarsGuide attended this event as a guest of the manufacturer, with travel, 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.

Bentley seems to have spent the design budget on the Continental GT Speed, which was launched at the same time and gets the same new engine under its slightly sexier bonnet. The big move there has been going from Bentley’s traditional four headlight face to a smoother more modern one with just two lights, or eyes.

The Flying Spur, by comparison, sticks with the more traditional look, and four eyes, but that doesn’t necessarily mean it looks nerdier. Indeed, it’s still an impressive and handsome beast and does a mighty fine job of making this much metal and mass look bold and desirable. 

Truly, vehicles this large tend to look lumpen and making one look as good this Flying Spur Speed does is an impressive feat. Look at the photos and be impressed.

The interior fit out and fittings are stunning, with Bentley boldly claiming it makes the best car cabins in the world. It’s not an outrageous claim, either.

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.

I’m not going to pretend that I had my laptop out taking notes while we were hitting 200km/h down the back straight at Magarigawa, but at more sane speeds there’s no doubt the rear seats of this car would be a very relaxing, plush, cosseting and pleasant smelling place to sit and work.

That’s at least partly what the Flying Spur Speed is for, a limousine for those who don’t like, or perhaps can’t quite afford, a Rolls-Royce, but still want great British solidity, class and that sense of obscene wealth, probably inherited.

The bonus of the Flying Spur is that it’s also a lovely place to be should you choose either of the front seats, with hugely comfortable seats that are more like couches, endless adjustability and many soothing massage settings for your heated and ventilated pews.

The spinning central 12.3-inch display remains the highlight, offering you a modern touch screen, which can disappear to reveal either three classic analogue dials or a plan piece of dashboard, if you prefer a “digital detox”.

Is “value” even a word that people use when they can afford to shop for a Bentley that costs $581,900, and will not be their only car? At very least, it’s a term that means something different to the people who breathe that kind of rarefied air.

The kind who have memberships to the exclusive Magarigawa Club where the Flying Spur Speed was launched. When just being a member costs a rumoured $1 million a year (and there’s a waiting list to get in), then half that much for a car probably isn’t so much.

The Flying Spur Speed comes with everything you would expect from a Bentley, incredible levels of comfort, a modern hybrid system that allows you to pretend you’re an eco-warrior while driving through the zero-emission zones of big cities like London and plenty of space and shiny things to look at.

The stereo is a Naim for Bentley audio system "arguably the finest in-car hi-fi available in any production car", while you also score a panoramic sunroof and mood lighting and even lovely deep-pile mats in the footwells. Ahh.

Sure, you could buy Ferraris and Lamborghinis for that kind of money, but they don’t have comfortable back seats like this Bentley, for those days when you really need to get to the chopper (parked on your personal helipad) in a hurry.

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.

If you’re going to put the word “Speed” in the title of your car, you really can’t mess about when it comes to the powerplant, and Bentley also has a proud history of making hugely powerful V12 engines to live up to. That’s a history that has now ended, with the announcement that the new 4.0-litre twin-turbo V8 in this Flying Spur Speed will be the one and only in all Bentleys, henceforth, including the Continental and the Bentayga SUV.

Bentley’s W12 engine is, sadly, no more, which might well make some older Flying Spurs quite collectable.

The V8 will come in different flavours, of course, and it’s also a hybrid, as is the modern way. Bentley calls the 140kW electric motor attached to the engine an “e-machine”.

Using that machine, the Speed can whisk you around in silent, EV-only mode for up to 81km. With such a stupendous sounding V8 on offer, it’s hard to see why you’d bother, but it’s an option, and the hybrid system is cleverly set up so that the harder you drive, the quicker the battery recharges, so effectively you’d almost never have to actually plug this PHEV in.

With the engine and e-machine combined, you’re looking at a staggering 575kW and 1000Nm, enough to propel all 2646kg of this Flying Spur Speed to 100km/h in just 3.5 seconds.

It might not sound quite as orchestrally moving as the big, sassy W12, but it’s still a hell of a replacement, as it is, in fact, “the most powerful Bentley engine ever”. That will do nicely.

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.

So, if you were very careful to use your 81km of EV-only range, as often as possible, and you drove very slowly and treated the accelerator pedal with great care, you might, possibly, achieve the Flying Spur Speed’s claimed fuel-economy of 10.7 litres per 100km. 

That’s the great thing about hybrids like this, they are theoretical fuel misers of the highest order. But if you aren’t careful and you care more about enjoying that twin-turbo V8 engine you’ve paid so much money for, you’re never, ever going to get it under 15L/100km, and you’ll quite likely exceed 20L/100km, as we did, with ease, by driving it around a track all day.

Theoretically, again, this Bentley will emit just 33 grams of CO2 per kilometre. 

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.

Any car with a whopping 575kW and 1000Nm is going to be interesting, even invigorating to drive, but you’d have to say the smaller and lighter it is, the more excitement, and even fear, you’re going to be faced with.

In the case of the Bentley Flying Spur Speed, you’re talking about an enormous, and enormously luxurious and comfortable, sedan that’s designed to carry more than two people, and weighs a hefty 2646kg.

It’s a limousine powered by a rocket, as I said earlier, but looking at the size, and pondering the weight of it, you really don’t expect too much in the way of thrills. Effortless performance, sure, titanic overtaking thrust, perhaps, but then you read the fine print and note that this Flying Spur Speed can hit 100km/h in 3.5 seconds.

That’s seriously fast in anything, but in a car this big, and filled with as much luxury as a mid-sized super yacht, it feels other worldly. 

Hammering the big Speed around a tight, intense race track feels strange at first and then strangely comfortable. Even sitting in the back wasn’t so much frightening as amusing, as the big Bentley simply slopes through any challenge you throw at it.

Sure, I’d like it to be louder, and you do miss the sound of the old 12-cylinder engine (and Bentley fans in particularly might find its absence upsetting), but the V8 is still throaty enough to please your ears, and it’s important to consider that it’s actually more powerful than the old W12, which is no mean feat.

Compared to the shorter, sharper Continental GT Speed we drove on the same day, the Flying Spur does have a bit more body roll, a bit more pitch and dive under braking from 200km/h, or when accelerating ballistically out of slow corners, but it’s still stupendously impressive for what it is.

And that is a luxury limousine that can turn itself into a race track weapon if you, and your three passengers, want it to. 

The Flying Spur Speed comes with 10 airbags and it has not been crash tested. Bentley also has its own 'Safeguard' suite of technologies including auto emergency braking, 'Swerve Assist' and 'Turn Assist'. 

Other tech includes 'Predictive Adaptive Cruise Assist with Lane Guidance', lane departure warning, emergency assist, remote park assist and 3D surround-view monitor.

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.

The Bentley Continental GT Speed comes with a five-year, all-inclusive servicing plan as standard.

That sounds good, but stunningly, Bentley still only offers a three-year manufacturer warranty, albeit one with no mileage limitations. That's way below industry standard these days.

The battery that forms part of the hybrid system is, however, warrantied for eight years, or 160,000km.