Mercedes-Benz E400 vs MG Im6

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.

A super solid first outing from the IM brand. Don't let the pricing fool you, there is still bang for buck on offer in the IM6 Performance, even if it at times feels a bit too digital for my tastes.

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.

I feel almost mean saying this, because there will be plenty of people who like the way the IM6 looks, and I don’t want to rain on their parade. But… I’m not one of them.

It reminds me a bit of the pre-facelift Tesla Model Y, in that it’s largely feature-less and a bit blobby, and there’s not a sharp angle anywhere to be found on the thing. Premium to me means powerful and assured — picture just about any Audi — whereas I just find this a bit bland and soft.

Anyway, I do like the big alloys, the insulated glass roof and the light treatment front and rear.

And I like the cabin. The seats aren’t leather, but they’re super thick and comfortable, and there is a genuinely premium air in the cabin, helped by the acreage of screens and the quality elements, like the little door panels.

The doors unlatch electrically, matching the pop-out door handles outside, but they can be a bit fidgety. Someone from MG told me how they worked (you kind of cover the handle and let the door come to you) but I watched everyone else who tried to open them struggle. If you're at the point where you have to explain how a door handle works, you might have over-egged the pudding.

The second screen below the main one acts a bit like a mobile phone. You can alter your home screen widgets and access the main menu, even as Apple CarPlay is synched at the top. You’ll get used to it, I’m sure, but I found it to be a bit fidgety.

Actually it reminds me a little bit of the Lexus trackpad, or whatever that hateful system was called, where you controlled the main screen via a little mousepad thing, though happily it’s nowhere near as annoying as that was.

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.

The IM6 measures 4904mm long, 1988mm wide and 1669mm tall, and it rides on a 2950mm wheelbase, with IM describing it as a "mid-large SUV", though I expect it will be classed as a medium SUV Australia.

That said, ICE and EV mid-size electric SUVs are not cut from the same cloth, with the latter making use of a flat floor to maximise space. And so it is with the IM6, where backseat room is pretty damn impressive. I’m 175cm, and I had no problem at all with legroom or headroom, plus the same plush seats from up there are in the back, too.

There are also air vents but no temperature controls, and while there are USB ports, there is no regular household-style plug in the cabin. 

The glass in the windows is laminated, while the roof is double glazed, which MG tells me is Australian summer-proof, but I guess we'll know for sure in a couple of months.

There’s no shortage of cargo room either. There’s a 32-litre frunk up front, and there’s 646 litres in the boot with the rear seats in place. They’re 60/40 split, and if you drop them, luggage space grows to 1621 litres.

The towing capacity is a braked 1500kg, too, but I don’t expect to see many of these towing a camper trailer around.

Premium play means more premium prices, and my IM6 Performance will set you back $80,990 on the road. That might have just sent your eyebrows skyward, but keep in mind it’s faster than some Ferraris, and is swimming with high-end tech, so the bang-for-buck factor is actually still pretty good.

There are cheaper ones, too. The single-motor Premium grade is $60,990 drive-away, albeit with less power and slower charging. Then there’s the Platinum, with a bigger battery and faster charging, which is $69,990

The Performance, though, gets everything IM has to give, including an 800-volt architecture, which means super-fast charging, as well as twin motors, brutal acceleration, a decent driving range and adaptive air suspension.

Elsewhere, you get LED lighting, a big and insulated glass roof, and 20-inch alloy wheels. Inside, there are thick and soft synthetic leather seats that are heated and cooled in both rows, a banging 20-speaker sound system, and wireless charging to pair with wireless Apple CarPlay and Android Auto.

There’s also 'active noise cancellation', and a seat-aware digital assistant which is about the best, and fastest, I’ve ever used. The IM6’s speaker system can locate where a voice is coming from, so any passenger can use the assistant. For example, if you’re in the backseat and say 'hey IM, lower my window', only your window opens. It’s a technology that I specifically remember the German brands crowing about not so long ago.

There’s also a 10.5-inch central touchscreen that controls much of the vast 26.3-inch screen that runs from in front of the driver to the centre of the cabin, as well as clever little magnets embedded in the dash in front of the driver, as well as in the back of the front seat headrests, that are designed to hold phones, iPads or other little accessories.

Also cool is the IM6’s self-parking tech, but there’s also a relatively useless crab walk function, which leans on the rear-wheel steering system to drive diagonally at slow speeds. I’m still not entirely sure when you’d use that one, to be honest.

Honestly, it’s a lot of stuff, and a lot of tech.

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.

This is the real party trick of the IM6, because there’s a nuclear power plant under the metal somewhere. All up, the twin-motor setup produces a total 578kW and 802Nm, though I suspect you’re never accessing all the grunt all at once. Still, 100km/h zips by in 3.4 seconds, and the top speed is 239km/h. For the record, that’s exactly as fast the Ferrari Roma Spider I recently handed back, so yeah, it’s properly supercar quick.

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.

Also on board is a 100kWh Nickel-Cobalt-Magnesium battery that produces a WLTP driving range of 505kms. Pretty good.

Charging is strong, too. The high-tech platform allows for 396kW DC fast charging, which is faster than what is currently offered in Australia. The claim is 30-80 per cent charged in 15 minutes. There’s also an external vehicle-to-load (V2L) port.

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.

First things first, don't get too distracted by the word "performance" here. The IM6 doesn't act like a performance car, it feels bit too plush, and bit too digital, for that.

But that's not necessarily a bad thing. Performance cars are often loud, raucous and uncomfortable, and the IM6 is none of those things. Instead, those mountains of power and torque make silky, silent progress absolutely effortless, which feels pretty premium to me.

MG makes a big deal of how much work went into insulating the cabin from noise – with active noise cancellation joined by double-paned insulated glass – and it is a properly calming and quiet space.

Also strong is the suspension, with the adaptive air setup soaking up most bumps and bruises, but I found it can clang over really solid bumps, sounding like it's bouncing off a stopper. The steering is solid, too, with a nice weight, if not overly talkative in the feedback department, while the rear-wheel steering helps eat into the turning circle for tight three-point turns.

The downside, though, is that it all feels a little too digital, and like there's been a little too much overthinking gone into it. Having to push a button to see behind you in a hurry is bonkers (see my explanation in the Safety section below), and the secondary screen is more annoying than intuitive. And there were several bings or bongs I couldn't even identify. All of which interrupts the otherwise calming nature of the drive experience.

There is a long list of safety aids on the IM6, and I won't detail the lot here. But I will call out a couple of curious mentions.

As always, the driver distraction warning is annoying, but can be switched off. And MG also counts the IM platform, or what it calls a digital chassis, as part of the safety offering. It has its own digital brain that adapts the air suspension, the rear-wheel steering and the active safety kit on the fly.

The other curiosity is the weird way you see out the back. Rather than fit a digital rear-view mirror to counteract the almost non-existent rear vision, you instead push up on a little toggle on the steering wheel to bring up a live view of what's happening behind you on the central screen.

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 IM6 is covered by a five-year, unlimited-kilometre warranty, rather than MG’S 10-year term. Capped-price servicing is offered for the first five years, with your total bill just under $3000. The service intervals are 20,000kms or 12 months.