Mercedes-Benz S350 vs MG Im6

What's the difference?

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.