Porsche 911 vs Mercedes-Benz E400

What's the difference?

The more things change, the more they stay the same. The t-hybrid might be an entirely new propulsion system for the 911, but the net result is unchanged – power, poise and performance on tap.

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

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.

This facelift debuts a revolutionary exterior design that has completely reshaped the 911.

Just kidding. If it ain’t broke and all that. The front air vents and exhaust have changed, the former now an active intake system that deploys via vertical flaps, but elsewhere it’s largely evolution over revolution.

Instead, Porsche has focused most of the updates in then cabin. In here, you’ll find a new digital instrument panel, they’ve changed some of the levers and the steering wheel.

In true Porsche fashion, though, this new 911 mimics the older versions in that it's one of the more intuitive cabins you’ll ever sit in. Everything feels as though it’s exactly where it should be, and all feels entirely centred on the driver.

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.

This probably falls under the ‘next question, please’ umbrella, given that, while the Porsche 911 is known for a lot of things, vast acres of space with loads of practicality perks just ain’t a part of its portfolio.

The new 911 measures a not-insubstantial 4533mm in length, 1852mm width and around 1294mm in height, and it rides on a 2450mm wheelbase. Luggage space is a paltry 135 litres under the bonnet, plus whatever else you can fit in your pockets.

There’s seating for four, should you not like the people you’re squeezing back there very much, but really the 911 is best enjoyed as a two-seat proposition – which is why you can also delete the backseat, should you wish.

It also weighs a minimum 1595kg, or up to 1745kg, but Porsche says the hybrid tech only adds about 50kg to the total kerb weight.

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.

At $157,400, the Cabriolet is the most expensive model in the E400 family, and is roughly $20k more than the sedan and $10k more than the coupe variants.

That money buys you a comprehensively kitted-out ride - as it really should - with the E400 Cabriolet arriving with 20-inch AMG alloys, LED headlights (made up of 84 LEDs) with high-beam assist, proximity unlocking with push-button start, air suspension and Merc's AIRCAP - a lip above the windscreen that's designed to push air up and over the cabin when the roof is down.

Inside, you'll find leather seats, dual-zone climate control and the clever 'AirScarf' system, which pumps hot air onto your neck when the roof is down (and it's cold out). You'll also nab heated front seats, power windows front and back and an automatic belt feeder, which saves you reaching over your shoulder to get to your seatbelt. So exhausting.

On the tech front, expect a killer 590W, 13-speaker Burmester stereo, controlled by the seriously impressive widescreen cockpit; two 12.3-inch screens that spill from about the centre of the dash all the way to the driver's binnacle, and control everything from navigation to Apple CarPlay and Android Auto.

There's a whole bunch of safety stuff, including semi-autonomous technology, but we'll drill down on that under the Safety sub-heading.

A new (or at least, massively altered) 3.6-litre petrol engine has been developed for this T-Hybrid, which combines with two electric motors to produce a total 398kW and 610Nm. It’s only available with Porsche’s very good eight-speed Porsche Doppelkupplung (PDK) automatic, largely because the brand admits it would be… well… unpleasant to drive as a manual.

Now, there is lots of magic at work here, and I don’t want to bore you, but the Porsche setup sees a lightweight 1.9kWh battery placed basically in the middle of the front axle, and a 12-volt battery now behind the front seat. Then, a tiny e-motor lives as part of the gearbox (it’s just 55mm long) and delivers up to 150Nm at low speeds to supplement the petrol engine.

It’s joined by what Porsche calls an “electric exhaust gas turbocharger”, which essentially removes the spooling time from the turbo, delivering instant power.

The aim of the game here is excitement, not efficiency, and the launch-control-aided spring to 100km/h takes just 3.0 seconds. And it somehow feels, and sounds, faster.

The latter being important, with Porsche aware that if the new powertrain didn’t sound good, "nobody would like it”.

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.

Porsche in Australia is yet to lock in local fuel use for the Carrera GTS T-Hybrid, but international testing has it at 10.5-10.7L/100km, C02 emissions of between 239-244g/km. 

Those aren’t exactly Toyota Prius numbers. But again, that was never Porsche’s intention. The electric power on offer here is intended to improve acceleration, not fuel use.

It’s fitted with a 63-litre fuel tank, which should deliver a driving range of around 600km per tank.

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.

Porsche did just about the Porschiest thing to ever Porsche in launching the 911 Carrera GTS T-Hybrid, in that we piled into cars in Melbourne, drove the many, many hours (well, it feels that long, at least) to the Phillip Island race circuit, beat the hell out of the cars on track and on the drag strip for several hours, then trundled back out on the road and drove them back to Melbourne.

The subliminal messaging here is pretty clear. This new 911 might have a new powertrain, but it can still deliver the road-track-road experience without breaking a sweat — or, more importantly, without breaking any expensive bits.

So let’s do this in order, shall we? On the road, this new 911 is every bit as sweet as it has ever been. Comfortable, quiet enough when you want it to be, and — save some road noise from those big wheels – quiet enough to let you forget you're driving something with one of Peter Dutton’s nuclear reactors hidden beneath its svelte metal work.

Mind you, that T-Hybrid powertrain will happily remind you of its presence every time you press the accelerator in anger, the exhaust erupting into life and the 911 genuinely rocketing into the future, but stay gentle with your inputs and this hybrid 911 is a genuinely comfortable, genuinely liveable daily driver.

Its split personality appears when you rumble out onto a race track though, where you quickly discover the electrified, and electrifying, Porsche is properly, properly rapid, both in a straight line or around Phillip Island’s fast and flowing circuit.

It’s so rapid, in fact, that it feels most closely related to a performance EV, like the Taycan. Of course it is louder and more engaging, but that’s the best way I can think of to describe the instant power on offer here. There’s no ICE-like lags or lumps in the way that 398kW and 610Nm finds its way to the tyres and into the tarmac. Instead it’s just this constant, savage flow of power that never seems to let up.

Porsche says this new powertrain is about 50kg heavier, but you’d need to be plugged into the race track like its the Matrix to ever feel it, with the T-Hybrid feeling lithe, grippy and athletic, aided by near-perfect steering, the best automatic gearbox in existence, and exactly zero roll through the body. In fact, the only thing that really moves when cornering hard in this new 911 is the driver, and I genuinely got out after several laps with a sore neck from trying to stay vertical.

Downsides? Well, it’s faster in a straight line (it will be some 7.0m further down the road after 2.5sec when compared to the older GTS) and faster around corners (8.7sec faster around the Nurburgring than its predecessor), but there’s something delightfully analogue about the outgoing car, which also manages to feel more aggressive under heavy acceleration, too, owing to the little ebbs and flows of power, and after driving both back-to-back, I still can’t decide which one I like more.

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.

There are few cars on the road as overloaded with safety technology as the E400 Cabriolet.

The standard stuff is all there, of course. There's a 360-degree parking camera, as well as nine airbags (dual front, dual pelvic/thorax for front-seat passengers, dual sidebags for rear passengers, dual head bags in the doors and a knee airbag for the driver), rollover protection and tyre-pressure monitoring, as well as braking and traction aids.

But the E400 adds some really clever technology, including Merc's Driving Assistance Package Plus, which adds active lane keeping, blind-spot assist, cross-traffic alert and evasive steering assist.

It's this suite of systems that allows the E400 to navigate freeways autonomously, including changing lanes on demand. At the moment, the system will warn you to keep your hands on the wheel every so often, but you can sense a time when that will no longer be required. And that time is soon.

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

The 911 Carrera GTS is covered by a pretty underwhelming three-year, unlimited-kilometre warranty, with servicing required every 12 months or 15,000kms. We don’t have the hybrid service pricing yet, but as guide, the last 911 split the services into minor and major, and charged either $785 or $1285 for each.

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.