Mercedes-Benz Gls450 vs Mercedes-Benz S400

What's the difference?

The new GLS is everything you’d expect of a Mercedes-Benz with an S in its name. Luxury, performance, space, and in this case, thoughtful practicality. A super-capable, super-sized family truckster with the lot.

The 2018 Mercedes-Benz S-Class remains a technological tour de force, a luxury sedan to be reckoned with - one that has safety, technology, comfort, finesse and performance all rolled into a stylish package. 

It's hard to see why you'd need anything more than the S 350 d, which is now much more attractively priced. It'd be my pick, but I'd have to get the Energizing Comfort Control package, and probably the AMG styling pack, too. And even then it would cost less than its predecessor.

Launched globally in mid-2019, Merc describes the GLS as the S-Class of SUVs, which is apt given its 5.2m length, 2.5-tonne mass, and ultra-premium specification.

As mentioned, the GLS is big; a step up from the already substantial model it replaces. Built with the US market in mind, in fact it’s produced in Tuscaloosa, Alabama, it’s more than five metres long, close to two metres wide, and over 1.8m tall. And there’s more than three metres between the axles, a 60mm wheelbase increase over the previous model.

And despite the size of the canvas, the Benz design team has managed to make the GLS look like a modern Merc. Signature elements include obvious ones like the slatted grille with a couple of three-pointed stars on the nose.

But there’s also, the carefully chiselled twin ‘power dome’ bonnet, scowling LED headlights and vents to aid front brake cooling and smooth aero performance around the front of the car.

The big beast’s off-road intent is highlighted by extensions around the wheelarches, with big optional 22-inch rims sitting underneath. The fact they look right-sized for the car speaks volumes about its scale.

The racy AMG Line package is standard, and a recess and pronounced character line, tightening the lower waistline is a familiar Merc treatment, plus alloy roof rails toughen the look while dialling up practicality.

The rear is relatively simple, borderline generic, with tapered tail-lights offering the only strong whiff of design personality. But believe it or not, thanks to careful detail sculpting of the body, and smoothing underneath the car it boasts a drag figure of Cd 0.32. Outstanding aero performance for a large SUV.

The driver and front passenger are presented with a sweeping dashboard dominated by twin 12.3-inch digital screens, one primarily covering the instruments, and the central screen managing the MBUX media system, including audio, nav, phone integration, car set-up, and more, plus ‘Hey Mercedes’ voice control.

The overall feel is simple, and restrained, yet massively confident, with a subtle colour palette, large squared-off elements defined by brushed metal finishes, and an obvious, intense attention to detail, from the haptic controls to the beautifully finished, multi-function steering wheel.

And the standard Burmester audio system includes a two-way in-car communication function that subtly amplifies the driver and front passenger’s voices for those in the third row, and vice versa. Sheer genius.

I swear it has been facelifted, and the changes are bigger than they might appear. There is no doubt that the S-Class shape is largely unchanged, but the German company has kept the modifications minimal in the scheme of things.

That doesn’t mean those changes are unnecessary, though. The new headlights, for example, are standard on every model, and are constructed with 84 LEDs (including three for the daytime running lights), and of course they’re adaptive with automated high-beam - meaning they’ll shield other road users from the glare of the lights at night. And the lights themselves will throw a main beam up to 650 metres, according to the company. 

Other things are slightly more cosmetic, like the revised three-bar grille treatment, new front and rear bumper designs that feature broader sculpted sections to widen the stance of the car, and there are new LED tail-lights as well.

The smallest set of wheels used to consist of 18-inch rims, but now the base car rolls on 19s, while the rest of the expansive range sits on 20s. 

The inside has seen some changes, too, but the appearance of things in the cabin isn’t the focal point - its the usability of the technology that's the big change. 

Oh, but I should tell you there are now 64 ambient lighting colours to choose from, which is up from seven, and now you can also set the lighting in three different zones - so theoretically you can have blue, orange and green areas of the cockpit, if you’re gross.

Space is obviously a critical factor here, and no surprise there’s copious amounts of it inside the GLS.

Front seat passengers enjoy plenty of breathing room, without feeling remote from one another, and there’s lots of storage in the shape of a large lidded box/armrest between the seats, a decent glove box, two big cupholders and jumbo door pockets with room for large bottles.

There’s one data-enabled USB port in the front, two charge-ports in the second row, and four in the third row. Shouldn’t be any complaints about powering mobiles, tablets or games.

The second row feels every millimetre the SUV limo. Simply getting in and out is made easier because an auto lowering function drops the car 25mm when one of the doors is opened.

I was able to sit behind the driver’s seat set for my 183cm position with heaps of head and legroom on offer. And there’s an extra 10cm of electrically adjustable travel to play with if those in the third row agree.

The fold-down centre armrest features a lidded storage tray and twin pop-out cupholders. There are netted pockets on the front seatbacks, and again, the door bins are big enough for large drink bottles.

Three adults across the rear is a breeze, there’s climate control ventilation, and a huge glass sunroof is standard. Rather than asking ‘Are we there yet?’ the kids will be disappointed when you arrive!

Then there’s what the Cleary family refers to as ‘the way back seat.’ A pair of third row seats for the lucky kids that get to inhabit their own little world. Getting in and out is relatively civilised thanks to electric slide and tilt for the second row seats, and space is generous. I could sit comfortably, so the kids will be all smiles.

With all seats upright cargo capacity is enough for a seven-person day trip (355L VDA). Press the button to fold the 50/50 split-fold third row down and your options expand substantially (890L). And with 40/20/40 split-folding second row lowered, transportation of a full, three-ring circus is on the cards (2400L). Overall, more space than the arch enemy BMW X7.

Plus, the ability to lower the car 50mm thanks to the standard air suspension makes life even easier. And one button lowers the second and third rows at the same time.

The spare is a collapsible space-saver, and towing capacity for a braked trailer is 3500kg, with a tow ball weight of up to 140kg. The ESP system also features a trailer stabilisation function that counters oscillation with “braking intervention.”

If you’re buying a Mercedes-Benz S-Class there’s a good chance you’re more interested in the back seat than the front: you could be buying it for a business, or you could like to be driven around - and there are definitely worse places you could be.

We would suggest, though, that the best place you could be if that’s your caper is in the back of a long-wheelbase S-Class model, which has extra legroom. 

And if you happen to be in a LWB model with the 'Business Class Package', you’ll enjoy two individual rear seats rather than a three-seat bench, folding tables for your bento box or laptop, and an ‘executive seat’ on the passenger side that features a foot rest and allows you to slide the front seat forward to liberate more room. Deluxe. 

No matter if you are in one of the stretched models demarcated as such by the ‘L’ suffix or not, you will enjoy excellent seat comfort and good head- and shoulder-room. Legroom in the regular models isn’t as plentiful as you might expect: much more affordable cars like the Hyundai Sonata give the S-Class a run for its money in that regard.

There are good storage options for odds and ends, with the back seat featuring a fold-down armrest with pop-out cupholders and a storage box, as well as map pockets - and the boot space varies depending on the model, but the S 350 d has a 510-litre cargo capacity (VDA). All four doors have bottle holsters, and a bit of extra room besides. Of course there are rear-seat air-vents, and if you’re kids are lucky enough to ride around in a S-Class, the two ISOFIX/three top-tether points will be welcome.

Up front there are two cupholders between the seats, and a new wireless phone charger in the centre console (Qi compatible phones only). There are two USB ports as standard in most models, while models with the rear seat entertainment package fitted get rear USBs. 

The huge screen that runs across two-thirds of the dashboard has seen the noticeable join marker removed for this update, with the monitors being upgraded to a higher resolution and the graphics have been reworked, too. The codpiece-style controller of the Comand media interface remains, and while it still isn’t as simple as other controllers, it is reasonably easy to get used to. 

So … what about Beyonce? 

She comes in as part of the Energizing Comfort Control system, which is standard in some models and a $1400 option in those that don’t have it fitted. 

Essentially it allows you to choose between different set moods: 'Joy', 'Freshness', 'Vitality', 'Warmth', 'Comfort' and 'Training', the latter of which offers three different stretching/exercise programs that last for 10 minutes to stop fatigue. The instructions are given by voice over the sound system.

Each of the moods will adjust the temperature and ventilation (the Freshness setting offers ‘gusts’ of fresh air as if you’re at the beach!), ambient lighting, air fragrance and intensity, and the massage function for the seats. And the music bit - there are predefined songs the system can cue up to suit the mood, or it can identify songs on a hard-drive or USB that suit the programs by analysing the tempo of the tune. Amazing, right?

The new steering wheel looks a lot sportier than the one in the pre-update car, and it has finally done away with the awkward cruise control stalk in favour of steering wheel buttons for the adaptive cruise control system.

If you can call a car that starts near two-hundred grand good value, then you have much more money than I do. But there is no escaping it: the new S-Class 2018 range is better value than before.

The starting point in the range is entry-grade S 350 d, which is $195,900 plus on-road costs. 

Standard kit for that model includes 19-inch alloy wheels, leather trim, heated and cooled front seats, nappa leather-wrapped steering wheel, those great new headlights and the new ambient lighting system, a panoramic sunroof, head-up display, dark brown 'Eucalyptus' trim, auto-dimming rear-view and side mirrors, a wireless phone charging system, keyless entry and push-button start. The entire S-Class range now gets auto-closing doors and an electric boot lid, too.

The media system in the S 350 d includes sat nav with traffic monitoring, a 13-speaker Burmester sound system, digital TV, DAB+ digital radio, Apple CarPlay and Android Auto, and the 'Comand Online' system with internet capability.

Next up the model range is the S 400d L (at $222,500), and the S 450 L ($227,500) - both of which are specified identically. Over the base model car they feature the extended wheelbase, as well as electronically adjustable rear seats with memory function, side window blinds, a rear blind, rear climate control, and 20-inch wheels. 

The S 560 sees the price head north to $270,000 (for the short-wheelbase model, which loses the abovementioned stuff in the L models), or $295,000 for the S 560 L. It adds the following nice features: nappa leather, brown burr walnut trim, a wood/leather steering wheel, 'Energizing Comfort Control', different (five-spoke design) 20-inch wheels, laminated glass and an anti-theft protection package. The S 560 L has luxury rear head restraints - they’re more like pillows, honestly - an individual rear-seat entertainment system and two wireless headsets.

The top of the regular S-Class model range is the Mercedes-AMG S 63 L, which is a princely $375,000. It builds on the kit offered in the models below, and pushes the sports luxury aspect further, with a full AMG body kit, 20-inch AMG wheels, AMG specific drive programs, AMG brakes, an uprated exhaust, sports steering and retuned suspension. Inside there are model-specific elements, special wood trim, front seats with active bolstering, and heated and ventilated rear seats.  

If you’re shopping at this end of the market, then you’ll likely also be tossing up between a BMW 7 Series, or maybe a Bentley Flying Spur. An all-new Lexus LS will arrive in April 2018, and the all-new Audi A8 isn’t far away, either.

There are two engines on offer. The 3.0-litre (M256) in-line six-cylinder turbo-petrol GLS 450 4Matic, and the 2.9-litre (OM656) in-line six-cylinder turbo-diesel GLS 400 d 4Matic.

The all-alloy, twin-scroll single-turbo petrol engine delivers peak power of 270kW from 5500-6100rpm, and maximum torque of 500Nm across a broad plateau from 1600-4500rpm. It also features a 48-volt electrical system driving the ‘EQ Boost’ set-up, able to deliver an extra 16kW/250Nm for short periods. The integrated starter-generator also enables energy recuperation.

Although the all-alloy, twin-turbo diesel features variable valve lift it gives some ground on power, offering up 243kW between 3600-4000rpm, but torque is a solid whack, with 700Nm on tap from 1200-3000rpm. Worth noting, that to minimise emissions this engine features a “selective catalytic reduction converter” in the exhaust, which brings with it the use of an ‘AdBlue’ reducing agent. The separate AdBlue tank has a capacity of 31.6 litres.

The nine-speed auto transmission is the same in both versions, although the diesel has a slightly lower final drive ratio.

The big news for the majority of S-Class buyers is the new engine in the S 350d, which is a 2.9-litre in-line six-cylinder turbo-diesel with 210kW of power and 600Nm of torque. It has a nine-speed automatic and is rear-wheel drive (RWD).

That same diesel engine is wicked up in the S 400d L, with that model churning out 250kW and 700Nm, and remains rear-drive with a nine-speed auto.

The petrol model range is opened by the S 450 L with a 3.0-litre six-cylinder twin-turbo mill producing 270kW/520Nm. Again, nine-speed auto, RWD.

The S 560 and S 560L run the same 4.0-litre twin-turbo V8 petrol with 345kW of power and 700Nm of torque. Nine-speed auto, rear-drive - naturally!

The AMG-fettled S 63 has a thumping twin-turbo 4.0-litre V8 petrol engine with 450kW and 900Nm, with a nine-speed MCT multi-clutch auto and - you guessed it - RWD.

Claimed fuel economy for the combined (ADR 81/02 - urban, extra-urban) cycle for the GLS 450 is 9.2L/100km, the more frugal GLS 400 d trimming that to 7.7L/100km. The petrol 450 emits 210g/km of CO2 in the process, the diesel 400d dropping that slightly to 202g/km.

Stop-start is standard, you’re looking at premium unleaded for the 450 GLS, and you’ll need 90 litres of dinosaur juice to full the tank on both models.

The diesel models are - unsurprisingly - the most frugal in the range, with the entry-level S 350 d using a claimed 5.4 litres per 100km across a range of disciplines.

The S 400 d L - which uses a higher-output version of the same diesel drivetrain as the model above - uses only a minuscule amount more: its claim is 5.5L/100km. 

The most frugal of the petrols is the S 450 L, with its six-pot petrol twin-turbo using a claimed 8.4L/100km.

Every model has stop-start - including the AMG - and the V8 petrols also feature cylinder deactivation when in 'Eco' mode.

That cylinder deactivation system helps the S 560 achieve an incredibly low claimed consumption of 8.5L/100km. So does the longer, slightly heavier S 560 L.

The higher-out Mercedes-AMG S 63 L uses 9.0L/100km, according to its claim. Amazing for the outputs of the engine.

Merc claims the GLS 450 will sprint from 0-100km/h in 6.2sec, and the 400 d in 6.3sec. Not hanging around for a 2.5 tonne mothership. But the standout is the 400 d’s torque. All 700Nm of it available from just 1200rpm to 3000rpm; right in the mid-range sweet spot.

The nine-speed auto transmission is smooth yet responsive, with paddles on the wheel for manual shifts when you want to pick the ratio. The combination of effortless grunt and the nine-speeder keeping things on the boil is an impressive one.

Suspension is by double wishbones at the front and multi-links at the rear, and while you can feel the weight in cornering, the standard Airmatic air suspension (which does away with steel springs) is superb in terms of ride comfort and body control.

We took a deep breath and pushed enthusiastically through a series of sweeping corners and the fat (285/45 fr - 325/40 rr) Continental ‘PremiumContact 6’ rubber wrapped around our car’s (optional) 22-inch rims gripped hard.

The ‘4Matic’ all-wheel drive system also seamlessly shuffles torque between the front and rear axles (theoretically up to 100 per cent in each direction).

Merc has put extra focus on body rigidity, the tuning of engine and suspension mounts, and sound absorption, and it shows. The GLS 400 d is beautifully refined on the highway. A neat touch is the car automatically lowering 15mm at motorway speeds or when ‘Sport’ mode is selected.

Steering is electromechanically assisted, and Merc says the front suspension geometry has been revised to minimise vibration through the wheel. And yes, feedback is minimal, but unfortunately so is road feel with only a general connection between your hands on the wheel and the front tyres on the bitumen.

When you’re steering a large beast like this, often with something substantial hitched to the back, you want to know braking performance is up to the task, and the GLS’s big ventilated discs all around deliver reassuringly strong stopping power, with nice, progressive pedal feel to boot.

The seats are adjustable six ways to Sunday, but beyond that they’re comfortable and supportive, even over long stints behind the wheel.

We stayed on the bitumen, because, let’s face it, that’s where this car will spend 99.9 per cent of its time, with the exceptions of the boat ramp, a ski weekend or pony club.

For those special occasions the optional ‘Off-road engineering package’ adds a low-range transfer case, inter-axle locking, hill descent control, and under body armour for more serious work.

Smooth. It wasn’t even because I’d chosen the Energizing Comfort Control mood to elicit that vibe. It’s smooth - and so it should be.

Whether it’s the near-silent new six-cylinder diesel, which hauls the near two-tonne sedan along with less fuss than a medical centre receptionist dealing with a room full of coughing patients. There is no fuss. You just hand over control to the engine, and trust it will get you where you need to be.

The V8 petrol in the S 560 also has a bit of a silent killer vibe to it. There’s perhaps not as much noise as a V8 fan might want, but the mumbo is there, and in both cars the gearshifts are sublimely timed and super smooth.

Admittedly, the stiff-sided run-flat tyres on both the 19- and 20-inch wheels can exhibit a slight terseness over sharp edges, but when it comes to rolling over pockmarked surfaces or rougher country backroads, the ride offered up by the air suspension with variable dampers is superb. Put it in Sport mode and it stiffens up to the degree you’d expect, but Comfort is no doubt the best place to be.

The steering is super light but accurate, meaning it’s easier than you’d think to pilot this behemoth of a sedan through corners. The grip on offer is excellent, too, even if traction can be an issue - I had a full couple of seconds of strobe light action from the traction control light when I buried the throttle in the S 560. 

I didn’t get a chance to drive the six-cylinder petrol S 450 L, or the S 400 d L. And, I’m really sad to report, there was no opportunity to drive the AMG S 63 L, either. 

But the overall feeling of the updated range is that it remains a deluxe and delightful limousine - whether you have the good fortune of being in the driver’s seat or not.

Easily one of the safest cars, if not the safest car, on the road today if technology is anything to go by. Well, we can’t go by a crash test score, because the S-Class hasn’t been crashed by EuroNCAP or ANCAP. So I can’t really give it a 10/10 for safety…

But when the standard safety kit list is as lengthy as the S-Class’s, it seems a safe bet. Items fitted include a 360-degree camera system, parking sensors front and rear, auto emergency braking, active blind-spot monitoring, active lane-keeping assist, adaptive cruise control with active steering assist, drowsiness detection, crosswind assist, and pedestrian detection with evasive steering assist (which allows you to turn the wheel harder to avoid impact with a pedestrian).

Plus there are other items like the company’s Pre-Safe crash detection system which can flash the car’s hazard lights at other road users, and tighten the occupant’s seatbelt in anticipation of being hit. And if that happens, there are eight airbags (dual front, front side, rear side, curtain).

The Mercedes-Benz range is covered by a three year/unlimited km warranty, which, like Audi and BMW continues to lag behind the mainstream market where the majority of players are now at five years/unlimited km, with some at seven years.

On the upside, Mercedes-Benz ‘Road Care’ roadside assistance is included in the deal for three years.

Service is scheduled for 12 months/25,000km (whichever comes first) with pricing available on an 'Up-front' or 'Pay-as-you-go' basis.

As a guide, service pricing for the outgoing GLS is set at $2600 per service (up-front) and $3250 (PAYG), a saving of $650 a pop. Fourth and fifth services are also available for pre-purchase ($3550 and $4900).

Mercedes-Benz offers a standard three-year/unlimited kilometre warranty.

Servicing is due every 12 months or 25,000km on all engines except AMG drivetrains, which require servicing every year or 20,000km. 

Mercedes-Benz has a (pricey!) capped-price servicing plan. The standard diesel and petrol models in the S-Class range cost $596 for the first service, and $1192 for the second and third visits. The costs for the sole AMG model is $736 for the first service, then the second and third visits are $1472 per.