Mercedes-Benz E400 vs Mercedes-Benz Gls450

What's the difference?

A convertible that doesn't feel like one when the roof is in place is no easy task to build, but it's one Merc's engineers have pulled off with the E400 4Matic Cabriolet. Effortless power, a tonne of technology and a comfy, leather-wrapped cabin all make Merc's drop-top E-Class a strong proposition.

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.

Elegance. That's the word that springs to mind when you first clamp eyes on the E400 Cabriolet. While the Coupe version has a crouched-over sportiness about its exterior design, the convertible is all about big and boat-like proportions, especially with the fabric roof opened.

Like nearly all drop-tops, the E400 looks best with the cabin open to the elements, and the side profile especially paints a picture of well-heeled wafting, with only the AMG alloys and body styling hinting at the performance on offer under the bonnet.

Inside, expect perfectly executed modern luxury, with soft leather seats, touchpoints that melt under the fingers and a sprinkling of woodgrain trim. All of which feel like old-world luxury, nicely juxtaposed by the huge twin-screen display that dominates the dash.

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.

It's a two-door, four-seat convertible, so practicality isn't at the very top of its list of strengths.

That said, life is peachy for upfront riders, both of whom will travel in spacious luxury. There are two cupholders hidden beneath a woodgrain cover underneath the climate controls - also home to a power outlet - as well as a clever double-hinged central storage bin that can be opened by either the passenger or driver, and which opens to reveal two USB points.

There's room in the doors for bottles, too, and the entertainment system can be controlled via a touchpad controller mounted above the traditional click wheel - although, to be honest, using it is harder and more time consuming than simply pretending it doesn't exist.

Climbing into the back (and we mean climb - there are no rear doors) is made easier by the fact you can fold and slide the front seats automatically by pulling a lever mounted near the headrest. Once there, though, you'll find space is a little tighter, and you feel weirdly cocooned, owing to the huge raised tunnel that runs through the middle of the cabin, and the low roof line.

There are two cupholders that live in the space where the middle seat would normally go, and there's a little bottle-holder cubby to the left of both backseat riders. There are air vents back there, too, but no temperature controls.

The front doors are huge and really very heavy, requiring considerable heft to open them.

The boot space is predictably a little limited, with 385 litres on offer. There's also a little flip-down separator, which shows you how much room the roof will need to come down, reducing boot space to 310 litres. Speaking of which, the soft-top can be lowered in just 20 seconds, and at speeds up to 50km/h.

One practicality quirk, though. The front (and only) doors are huge and really very heavy, requiring considerable heft to open them, especially if you're parked on a slight angle. Honestly, I was reduced to kind of pushing them open with my foot at times.

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.”

The GLS launches in Australia with two models, the turbo-petrol GLS 450 4Matic at $146,500, before on-road costs, and the turbo-diesel GLS 400 d 4Matic at $153,300.

Specification is identical across the two variants, and when you’re competing against the likes of the Lexus LX570, Audi Q7 and BMW X7, as you might expect the list of standard features is lengthy.

Aside from the comprehensive suite of safety tech, covered in the Safety section below, the GLS equipment list includes, 21-inch alloy rims, adaptive high beam assist, air suspension, alloy roof rails, AMG body kit, a huge panoramic sliding glass sunroof, privacy glass from the B-pillar back, auto tailgate, keyless entry and start, rain-sensing wipers, cruise control, LED headlights, and power closing doors.

The power closing doors are a big plus for parents not wanting to disturb kids nodding off in the car, with the soft-touch function drawing the door in for the last few millimetres to an almost silent close.

Inside there’s ambient lighting (64 colours), strategically placed open pore oak wood trim, 13-speaker/590-watt Burmester surround sound audio, electric folding second and third row seats, a head-up display, ‘Mercedes-Benz’ branded illuminated sills, leather seat upholstery (‘Artico’ faux leather on the dash and doors), multi-adjustable electric seats in the front and second row (memory in the front), electrically adjustable steering column, leather-trimmed multi-function steering wheel, and five-zone climate control.

The multi-media system is spectacular, incorporating the twin 12.3-inch digital screens, the central media unit managing nav, digital radio, mobile device connectivity, Apple CarPlay and Android Auto, plus vehicle tracking. There are also remote vehicle status functions (door locking, valet parking, etc), global search (Amazon Alexa, Google Home, Yelp, and Trip Advisor), and a wireless device charging pad.

The basket of goodies can hold its head high in this part of the market, so the value equation stacks up well.

It's a fabulous engine, this twin-turbocharged V6 - even if it doesn't feel quite so lively in Cabriolet form as it does in the hardtop equivalents.

The 3.0-litre unit produces 245kW/480Nm, sending it to all four wheels via a nine-speed automatic transmission, linked to the standard 4Matic all-wheel drive system.

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.

Mercedes claims 7.4L/100km on the combined cycle (but you can expect to be pushing nine litres in real-world conditions), with emissions pegged at 170g per kilometre of CO2.

The 66-litre tank will only accepts 95RON fuel.

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.

Sure, the E400 Cabriolet can drive itself, but we’re equally pleased to note that it’s still a lot more fun handling the steering duties yourself.

And that is mostly due to that fabulous engine; quiet and effortless at city speeds, rorty and enthusiastic at pace, and genuinely angry with the drive setting switched to their most hardcore Sport+ mode.

We’ve already spent time in the sedan version, and while this Cabriolet is heavier (1935kg vs 1820kg) and slightly slower to 100km/h (5.5sec vs 5.2sec) it doesn’t immediately feel it behind the wheel, with a similar and satisfying lurch into the future when you plant your foot.

But hard charging is not what this car is about, and the E 400 is at its peachy best when rolling about the city or the ‘burbs with the top down, and the warm summer air washing through the cabin.

In its normal drive settings, the steering is light but engaged, and the ride on offer from the standard air suspension is outstanding, cosseting the cabin from all but the very worst road imperfections, while the torque from the V6 serves up effortless, unobtrusive acceleration.

With the roof up, Merc’s designers have done a stellar job of hiding the fact this thing is a convertible at all. It’s a solid-feeling cabin with the fabric roof fastened, and the cabin is quiet and free from wind noise.

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.

At the time of this launch drive the GLS hadn’t been safety assessed by ANCAP, but you could make a small wager, like every penny you have to your name, that it will score a maximum five stars.

The expected active features are there, including ABS, ASR, and ESP, with additional tech including ‘Active Blind-Spot Assist’, ‘Active Brake Assist' (Merc-speak for AEB), active lane keeping and lane change assist, ‘Adaptive Brake’, ‘Attention Assist’, ‘Evasive Steering Assist’, ‘Parktronic’ (active parking assist with 360-degre camera), rear cross-traffic alert, traffic sign assist, and a tyre pressure warning system.

Then, if all that isn’t enough to avoid an impact the GLS is equipped with nine airbags (front and pelvis side for driver and front passenger, side for outer rear seat occupants, full-length curtain, and a driver’s knee bag), an active bonnet to minimise pedestrian injuries, and the ‘Pre-Safe Plus’ (flashes rear hazards to warn drivers closing too quickly from behind, tightening the belts at the same time, and locking the brakes if the GLS is stationary with a rear impact imminent).

Expect the usual three-year, unlimited-kilometre warranty, with service intervals pegged at 12 months or 25,000km. Mercedes' capped-price servicing scheme limits maintenance costs to $2280 for the first three years of ownership.

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).