There's clever. Then there's the Mercedes-Benz E400.

Andrew Chesterton road tests and reviews the new Mercedes-Benz E 400 with specs, fuel consumption and verdict. 

Forget engines, interior materials and even exterior design; there’s a new Ground Zero in the battle for premium sedan supremacy, and that’s on-board smarts.

What began innocuously enough with automatic handbrakes and the slow death of the manual gearbox is now steaming at pace toward a future where humans will likely only feature on the optional extras list. BMW’s new 5 Series, for example, can pretty much drive itself for spells of 30 seconds, while Audi’s A6 can be fitted with better night-vision tech than SEAL Team Six.

But the E-Class just might pip them both. And that’s because Mercedes has thrown everything it’s got at its iconic saloon – including some stuff it’s borrowed from its S-Class flagship – to tackle the best its German competitors can muster. This E-Class drives itself, parks itself, changes lanes on demand and will scream to a complete stop from 100km/h in an emergency without you having to touch the brake. And that’s only part of the story.

But if there’s to be a human uprising against our autonomous overlords, then it will start from behind the wheel of cars like the E 400 4MATIC. It’s the top-spec petrol in the E-Class line up (save the AMG-stamped model), and it’s hiding a potent twin-turbo V6 under its bonnet. And that means you won’t be relinquishing the driving duties without a fight.

Does it represent good value for the price? What features does it come with?

The E 400 4MATIC arrives with a $139,900 price tag. That’s more than the new BMW 540i ($136,900), and enough to punch a sizeable hole in all but the most robust of budgets.

The good news, then, is that you’re not left with many options to tick. Outside, the E 400 4Matic sits on 20-inch AMG alloys, while the headlights are a nest of clever LED bulbs. The panoramic glass sunroof is standard fit, too, as are the polished aluminium strips that ring the windows.

You can expect good things to be happening under that bonnet.

Inside, expect supple leather, a beautifully crafted dash and a liberal sprinkling of open-pore wood. Entertainment and information duties are handled by a very cool twin-screen set up, in which two 12.3-inch, high-resolution screens (one that acts as a centre screen, and another that acts as a driver display) appear joined, running smoothly from the centre of the cabin all the way to the driver’s edge. The system pairs with a Burmester stereo that plays through 13 speakers. And if that’s not enough technology, there’s also a head-up display beamed onto the windscreen.

Elsewhere, expect dual-zone climate control, heated front seats, a steering wheel wrapped in Nappa leather and an intricate ambient interior lighting system that allows you to pick from what feels like every colour in the rainbow.

But the big news, of course, is the safety and semi-autonomous technology, but we’ll come back to that under the Safety heading.

Is there anything interesting about its design?

The hits just keep on coming for the Mercedes design team. The entire E-Class range is a masterful study in blending polish and potency, but none do it better than the E 400 4MATIC. And we’re head-over-heels with the look of it.

The addition of those huge 20-inch alloys wheels, plus the bulging bonnet and twin, trapezoid exhaust tips add a sense of menacing purpose to what is otherwise a sleek and expensive-looking sedan. The only view that lets it down is side-on at the front end, where the new 3D housing that surrounds the three-pointed star bulges forth from the bodywork, looking a little like something that might require lancing.

Inside, expect a stylish, uncluttered and perfectly executed dash dominated by the twin-screen setup  (though, we’re not sure they’ll fly with the brand’s loyalists), and a premium and luxurious feeling cabin - though it can feel a little tight in the backseat.

How practical is the space inside?

Like most in this bracket, the E 400 4MATIC is aimed at pleasing the driver, with the other passengers somewhere down the pecking order. As a result, life in front - and especially in the driver’s seat - is a treat. The well bolstered seats are supportive and comfortable, and vision is terrific. The slightly driver-focused screens make analysing driver data or navigation instructions a breeze, too.

The two front seats are separated by a leather and piano black centre console, with two cupholders hiding under one of the shiny panels. There’s another two hidden in a pull-down divider that separates the rear seats, and backseat riders also get their own power outlet. Disappointingly, though, there’s no individual air-con temperature controls in the back, but your passengers can turn their vents on or off.

There’s plenty of legroom for backseat passengers, but if you’re cresting 183cm (six foot) then your head will be scraping the ceiling trim. There are two ISOFIX attachment points, one in each window seat in the back, and you'll squeeze 540 litres into the shallow but long boot.

What are the key stats for the engine and transmission?

This is the biggest and baddest model in the E-Class line up (at least, of those that haven’t undergone the AMG treatment), and you can expect good things to be happening under that bonnet.

Power arrives courtesy of a twin-turbo V6 that will produce 245kW at 5250rpm and 480Nm from 1400rpm (to put that into perspective, the E43 AMG model is good for a not much more 295kW and 520Nm), with the grunt sent to all four wheels via a very good nine-speed automatic transmission. All of that helps produce a 0-100km/h sprint of around 5.2 seconds and a top speed of 210km/h (electronically limited).

How much fuel does it consume?

Well, that depends who you ask. The official reading is pegged at claimed/combined 8.4L/100km, but we were well north of 10 litres by the time we’d finished our test. Part of the problem, we’re sure, is how tempting it is to unleash all of the engine’s power every time you pull away from a light. The E 400 4MATIC’s C02 emissions are listed at 191g/km.

What's it like to drive?

Other-worldly. The thing about pumping all that technology into a model is that it inevitably overshadows a car's more traditional skill set. So we rushed out to our closest freeway and set about being driven along with nothing but the E 400 4MATIC's digital brain keeping us off the very solid-looking concrete looking divider that separates the M5 Motorway in Sydney.

It is undeniably clever stuff. And on a grey and rain-soaked afternoon, more than a little terrifying. Benz’s semi-autonomous stuff is an advance on existing lane-keep assist and adaptive cruise control technology, tapping into those systems to ensure the E 400 4MATIC stays within the lane markings and keeps a safe distance from the car in front.

But the E-Class also adds the ability to change lanes, simply by holding down the left or right indicator. The car will then shift by itself as soon as it thinks it’s safe to do so. It's a weird sensation, and it takes some getting used to. But its also difficult to immediately see its usefulness, and I doubt it would be getting too much use in the real world (after the owners show all their friends, of course).

The good news, though, is that the E 400 4MATIC shines when you wrestle control of the wheel back. The V6 engine is effortless in its power delivery, and it pairs seamlessly with the sharp shifting nine-speed automatic transmission. The steering, too, is engaging enough, but we were left most impressed by the E 400's ride quality. Merc's multi-chamber air suspension arrives as standard kit, and it does a commendable job of ironing out all but the harshest of Australia's dodgy road surfaces. If your day is centred in the CBD then the E 400 will happily waft you from meeting to meeting, locking bumps, road noise and other annoyances outside of the cabin.

Switch from the Comfort drive setting to Sport or Sport+, however, and the E 400 4MATIC switches gear, bristling and burbling and hardening at every contact point. Keep it in this mode and find a twisting back road and the idea of a car that drives for you feels very far away indeed.

What safety equipment is fitted? What's the safety rating?

Technically, the E 400 4MATIC is safer without you touching anything, with the human doofus behind the wheel the one variable it can’t control. And one day soon, that will undoubtedly be the only way to travel.

For now, expect nine airbags (front, pelvis and window in the front, curtain airbags for the rear and a knee airbag for the driver), a 360-degree parking camera and hill start assist, along with Merc’s 'Attention Assist' program that will monitor your inputs to see if you’re getting drowsy.

But the really clever stuff arrives as part of the 'Driver Assistance Package Plus', which includes lane keep assist and adaptive cruise control, but this is also the closet thing to an autonomous car that Merc’s got in its stable. So the E 400 4MATIC will keep up with traffic on the highway, and keep within the lane markings even as you turn around a corner. It will also change lanes for you when you hit the indicator, and scream to a stop if there's an emergency.

There's some truly clever crash detection systems, too. If the E 400 senses a t-bone collision, for example, your seat will jolt you away from the point of impact. And if it senses a rear collision, a high-pitched sound will play through the speakers, preparing you ears for the sound of the impact and minimising the chance of eardrum damage.

The E-Class range scored the maximum five star ANCAP safety rating when crash tested in 2016.

What does it cost to own? What warranty is offered?

Like the rest of the E-Class family, the E 400 4MATIC is covered by a three-year/unlimited km warranty, and this one will require a trip to the service centre every 25,000km or 12 months.

It also falls under the German brand’s capped price servicing program, which limits maintenance costs to $2280 for the first three services.

Verdict

It might push us ever closer to an autonomous future, but it's also a solid reminder of how much fun can be had behind the wheel. Potent, polished and with an engine that's a treat in the city and on a twisting back road, the E 400 4MATIC might just be the pick of the premium sedans.

Do you like the sound of Merc's new E 400? Tell us what you think in the comments below.

Click here to see more 2017 Mercedes-Benz E-Class pricing and spec info

This story originally appeared on CarsGuide