MG Im5 vs Mercedes-AMG GLE63

What's the difference?

The MG IM5 Performance is fast, comfortable, quiet and super refined. Putting some minor spec and active safety niggles to one side, it offers the features, tech and price to match it with its well-credentialled and already popular mid-size EV sedan competitors. Is there room for one more? We think there should be.

There’s little wonder the GLE63 S is back for a second go around, after  clearly putting the frighteners on the Audi RS Q8 and BMW’s X5 M Competition and X6 M Competition.

After all, it’s a large SUV that sacrifices little in the way of practicality (especially the wagon) in its pursuit of high performance.

And for that reason, we’re itching to go for another drive – with or without the family.

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

Playing spot the straight line on the outside of the MG IM5 is like an automotive design version of Where’s Wally? There aren’t many, in the midst of an unrelentingly curvaceous exterior treatment.

At close to five metres long and two metres wide the IM5 is appreciably longer (+211mm), a little wider (+27mm) and a bit taller (+33mm) than a Tesla Model 3. Think BMW 5 Series in terms of overall size.

And the soft-form shape is functional; the swoopy liftback boasting an ultra-slick 0.24 drag coefficient.

That said, I’m not convinced by the ‘Periscopic’ cameras informing the driver assistance systems from the front guards. They scream tacked-on afterthought. But a touch-only initial opening function for the flush door handles is cool and makes life easier.

The curves continue inside with soft-padded surfaces around the dash and doors, but the straight edge obviously came out for the 10.5-inch central media screen and vast 26.3-inch upper display. There are next to no buttons; even exterior mirror adjustment is directed from the screen to a multi-function steering wheel control.

System software (powered by a Qualcomm ‘Snapdragon’ chip) is lightning fast with a two-finger up and down swipe shortcut function on the central screen for ventilation and other functions.

The interior is light and bright thanks to the enormous panoramic sunroof. It’s been fine in cooler winter conditions during this test but it could be interesting to revisit in the heat of an Aussie summer

There are two interior colour schemes available - the ‘Highland Grey’ of our test car or ‘Dover Beige’ for those brave enough to live life with the threat of scuff marks on your shiny new car’s glamorous but vulnerably light interior.

First things first, the new GLE63 S is available in two body-styles, with the wagon appealing to the traditionalists out there, while the coupe targets the style-conscious.

Either way, few large SUVs are as imposing as the GLE63 S, which is a good thing considering it wants to be taken seriously.

Up front, it’s immediately identifiable as a Mercedes-AMG model thanks to its distinctive Panamericana grille insert.

The angry look is punctuated by the angular daytime running lights integrated into the Multibeam LED headlights, while the chunky front bumper has large air intakes.

Around the side, the GLE63 S stands out with its aggressive wheelarch extensions and side skirts, with the wagon getting 21-inch alloy wheels as standard, while the coupe gets 22-inch items.

From the A-pillars onwards, the differences between the wagon and coupe body-styles start to become apparent, with the latter’s roofline much more steeply raked.

At the rear, the wagon and coupe differentiate themselves even more clearly with their unique tailgates, LED tail-lights and diffusers. That said, they do have a sports exhaust system with squared-off quad tailpipes in common.

It’s worth mentioning that the difference in body-style also means a difference in dimensions, with the coupe 7mm longer (4961mm) than the wagon, despite having a 60mm-shorter wheelbase (2935mm). It’s also 1mm narrower (2014mm) and 66mm shorter (1716mm).

Inside, the GLE63 S separates itself with its flat-bottom steering wheel with Dinamica microfibre accents, and multi-contour front seats, which are upholstered in Nappa leather alongside the armrests, dashboard and door shoulders and inserts.

The door bins are of the hard plastic variety. That’s underwhelming in a vehicle that costs this much, as you would hope cow hide – or at least a soft-touch material – would be applied to them.

The black headliner acts as another reminder of its performance focus, and while it makes for a darker cabin, metallic accents feature throughout, while the trim (our test vehicle had open-pore wood) adds some variety alongside the ambient lighting.

That said, the GLE63 S is still filled to the brim with cutting-edge technology, including two 12.3-inch displays, with one the central touchscreen and the other a digital instrument cluster.

Both use Mercedes’ MBUX multimedia system and feature Apple CarPlay and Android Auto support. This set-up is still the benchmark, thanks to its speed and breadth of functionality and input methods, including always-on voice control and a touchpad.

There’s plenty of breathing room up front and in terms of storage one of the first things worth calling out are the long but relatively narrow door bins. No good for anything above unusually slender bottles, even if they’re lying down.

No conventional glove box in the dash, but there is a large lidded box (cooled and heated) between the seats that doubles as a centre armrest. It’s supplemented by a big stowage area underneath the flying buttress style centre console.  

There are two cupholders in the centre console as well as a wireless device charging pad in front of them with a vaguely phone-shaped oddments bin alongside it.  

Move to the rear and the IM5’s 75mm wheelbase advantage over the Tesla Model 3 is clear. Heaps of knee and headroom for me at 183cm sitting behind the driver’s seat set to my position. 

But… the seat sits low which pushes your knees up into the air to the point where my thighs are not contacting the seat cushion. Even though the rear seat reclines to a certain degree it’s a problem compounded by a chronic lack of room for your toes under the front seat. Awkward.

There are map pockets in the front seatbacks, modest bins in the doors and a fold-down centre armrest with two cupholders. Adjustable ventilation in the rear of the front centre console always makes life in the rear seat more pleasant.

The car also houses ‘Strong Magnets’ at various points around the cabin and boot, with a configurable adapter able to lock a phone or tablet into place for the entertainment of, in our case, back seaters. 

Speaking of devices for entertainment, there are two USB-C sockets and a 12-volt outlet in the front and another USB-C and 12V in the back, so charging isn’t an issue. 

The IM5 is a liftback so the boot aperture is generous and a capacity of 457 litres with the rear seats up is decent for a car of this size, although that’s less than the Tesla Model 3 (594L) which has an additional well under the floor. 

Still, enough room for the largest (124L) and smallest (36L) suitcases from the CarsGuide three-piece luggage set with some room to spare.

The power tailgate can be operated hands-free via the key or an always welcome under bumper kick function.

Volume expands to 1290 litres with the rear seats folded and there’s a modest 18-litre ‘frunk’ under the bonnet.

The bad news is a repair-inflator kit rather than a physical spare wheel, but the better news is the IM5 Performance can tow a 1500kg braked trailer (750kg unbraked).

The IM range also features the ‘MG iSmart’ app allowing remote control of various functions including charging, checking vehicle location and route planning. 

Being a large SUV, you’d expect the GLE63 S to be quite practical, and it is, but what you wouldn’t expect is the coupe to have 25L more cargo capacity than the wagon, at a generous 655L, due to its higher window line.

That said, when you stow the 40/20/40 split-fold rear bench via the second row’s release latches, the wagon has a significant 220L advantage over the coupe, at a cavernous 2010L, thanks to its boxier design.

Either way, there’s a small load lip to contend with, making loading bulkier items a little more difficult, although that task can be made easier with the flick of a switch, as the air springs are able to lower the load height by a handy 50mm.

Better yet, four tie-down points are on hand to help secure loose items,  alongside a couple of bag hooks, while a space-saver spare resides under the flat floor.

In the second row, things are even better, with the wagon offering a crazy amount of legroom behind our 184cm driving position, as well as two inches of headroom for me.

With its 60mm-shorter wheelbase, the coupe naturally sacrifices some legroom, but it still provides three inches of legroom, while its sloping roofline trims headroom to an inch.

No matter the body-style, the five-seat GLE63 S is wide enough to seat three adults abreast with few complaints, with the transmission tunnel on the smaller side, meaning there’s plenty of room for feet.

There’s also plenty of room for child seats, with two ISOFIX and three top-tether anchorage points on hand for fitting them.

Amenities-wise, rear occupants are treated to map pockets on the front-seat backrests, as well as a fold-down armrest with two cupholders, while the door bins can accommodate a couple of regular bottles each.

A  fold-out cubby is positioned below the air vents at the rear of the centre console, containing two slots for smartphones as well as a pair of USB-C ports.

In the first row, occupants have access to the centre console’s cubby, which features two temperature-controlled cupholders, in front of which are a wireless smartphone charger, two USB-C ports and a 12V power outlet.

The central storage bin is pleasingly large and contains another USB-C port, while the glovebox is also on the larger side, and you get an overhead sunglasses holder too. Stunningly, the front door bins can take three regular bottles apiece. Not bad.

While the wagon has a large, square rear window, the coupe’s is a letterbox in comparison, so rearward visibility isn’t one of its strong suits.

Priced from $220,600 plus on-road costs, the new GLE63 S wagon is $24,571 dearer than its predecessor. While the rise is unfortunate, it is accompanied by the fitment of a lot more standard equipment.

And the same is true of the new GLE63 S coupe, which is priced from $225,500, making it $22,030 more expensive than its forebear.

Standard equipment for both cars includes metallic paintwork, dusk-sensing lights, rain-sensing wipers, power-folding side mirrors with heating, side steps, soft-close doors, roof rails (wagon only), keyless entry, rear privacy glass and a power-operated tailgate.

Inside you score push-button start, a panoramic sunroof, satellite navigation with live traffic, digital radio, a 590W Burmester surround-sound system with 13 speakers, a head-up display, a power-adjustable steering column, power-adjustable front seats with heating, cooling and massaging functionality, heated front armrests and outboard rear seats, four-zone climate control, stainless-steel pedals and an auto-dimming rearview-mirror feature.

Rivals for the GLE63 S include the less expensive Audi RS Q8 ($208,500) and BMW’s X5 M Competition ($212,900) and X6 M Competition ($218,900).

The MG IM5 Performance is powered by an electric motor on each axle - the rear (372kW/500Nm) more powerful than the front (200kW/300Nm), for overall outputs of 572kW (that’s close to 770hp) and 802Nm of pulling power.

The official term for that amount of grunt is… a lot. And we’ll get to what it means on the road in the Driving section shortly.

The GLE63 S is powered by Mercedes-AMG’s ubiquitous 4.0-litre twin-turbo V8 petrol engine, with this version pumping out a hard-hitting 450kW of power at 5750rpm and 850Nm of torque from 2250-5000rpm.

But that’s not all, because the GLE63 S also has a 48V mild-hybrid system called EQ Boost.

As its name suggests, it has an integrated starter-generator (ISG) that can provide up to 16kW and 250Nm of electric boost in short bursts, which means it can also reduce the sensation of turbo lag.

Mated to a nine-speed torque-converter automatic transmission with paddle-shifters, and Mercedes-AMG’s fully variable 4Matic+ all-wheel-drive system, the GLE63 S sprints from a standstill to 100km/h in just 3.8 seconds, in either body-style.

The MG IM5 Performance features an 800-volt electrical architecture which means the 100kWh NCM battery can accept a DC peak charge of close to 400kW.

Only snag is the highest you’ll currently find in Australia is 350kW. But even at that rate you’ll still be looking at a 30-80 per cent charge in just over 15 minutes. Maximum AC charge rate is 11kW.

Claimed range is 575km (WLTP) which is less than the Tesla Model 3 Dual Motor AWD at 629km.

Over a week of city, suburban and some freeway running we saw average energy use of 20.6kWh/100km which is on the high side for an EV of this size but maybe not for one with this kind of performance potential. 

The GLE63 S’s fuel consumption on the combined-cycle test (ADR 81/02) varies, with the wagon achieving 12.4L/100km, while the coupe needs 0.2L more. Carbon dioxide (CO2) emissions are 282g/km and 286g/km respectively.

When you consider the high level of performance on offer, all of these claims are fairly reasonable. And they’re made possible by the engine’s cylinder-deactivation technology and the 48V EQ Boost mild-hybrid system, which has coasting and extended idle-stop functionality.

That said, in our real-world testing with the wagon, we averaged 12.7L/100km over 149km. While that’s a surprisingly good result, its launch drive route mainly consisted of high-speed roads, so expect a much higher number in metropolitan areas.

And in the coupe, we averaged a higher but still respectable 14.4L/100km over 68km, although its launch  route purely involved high-speed country roads, and you know what that means.

For reference, the wagon has an 80L fuel tank, while the coupe has an 85L unit. Either way, the GLE63 S only takes more expensive 98RON premium petrol.

First things first, the IM5 Performance is supercar fast. This 2.3-tonne five-seater blazes from 0-100km/h 3.2 seconds and with its dual motors combining to produce 572kW/802Nm, eye-widening performance always resides underneath your right foot.

But it’s not all about straight line speed. Ride comfort is excellent. Underpinned by an all-new platform, the IM5’s suspension is by double wishbones at the front and multi-links at the rear. But the key to its bump and rut smoothing ability is air suspension and ‘continuous control’ active damping.

Fold in double-glazing on the full-length glass roof and side windows, as well as active noise cancellation and you have a serene interior environment at any speed. Also worth noting the front seats are great; as grippy as they are comfortable.

Not only that, despite its relative heft, this mid-sizer steers well, too. Not the last word in road feel but it points accurately and the standard rear steering helps with prompt (but never jerky) cornering turn-in. Flick to ‘Sport’ mode and the IM5 is up for some enthusiastic running.

The rear wheels can turn up to 12 degrees in the opposite direction to the fronts at slow speed, which makes for a usefully tight 10-metre turning circle. But above that, at lesser angles, it adds extra stability and decisiveness in the way the car steers through even tight, twisty sections.

Rubber is top-shelf Pirelli P Zeros on 20-inch alloys (245/40 fr - 275/35 rr) and it grips hard, especially in the wet weather over much of the test period. Braking is solid, as it needs to be, with ventilated discs all around and four-piston callipers at the front. 

No adjustable regen braking but you can feel the ‘Cooperative Regenerative Brake System’ (CRBS) doing its thing when you lift off the accelerator. 

The physical rear view is modest thanks to the slope of the back window reducing its functional area for the driver to that of a 1950s VW Beetle. Even the interior rear-view mirror is tiny and folds up into a recess in the headliner if you’d prefer life without it.

But that’s where a rear camera view popping up on the upper screen display (accessed via the right-hand steering wheel click control) comes in handy. Side camera views are also available as is a 360-degree overhead view, which makes parking straightforward.

If you need more parking help there are various self-parking modes including a nifty ‘Curbside’ function that will realign the car hands-free if you’re parallel parked too far out from the kerb.

In a similar vein, a ‘Rainy Night’ mode projects left and right rear views onto the main screen using AI to enhance clarity and highlight pedestrians and cars.

Overall the ADAS (Advanced Driver Assistance Systems) are relatively unobtrusive but we found ourselves switching off the incessant overspeed chime that sounds for 10 seconds if you creep over the indicated speed limit, even when the system has misfired on the correct speed. For example, 40km/h school zones on a Sunday.

The over-zealous driver distraction warning also occasionally issued a visual and audible slap on the wrist when I was looking straight ahead. Tellingly, there’s a specific quick screen for turning both these functions off, but it kinda defeats the purpose of having them in the first place.

We also found the adaptive cruise control to be hesitant in multi-lane environments, reducing speed occasionally because the system seemingly believed a car was set to merge, when it wasn’t.

Make no mistake, the GLE63 S is a big beast, but it certainly doesn’t act its size.

Firstly, the GLE63 S’s engine is an absolute monster, helping it to hunker down off the line and then charge on towards the horizon with serious vigour.

While there’s so much initial torque to begin with, you still get the added benefit of the ISG, which helps to eliminate lag as the new twin-scroll turbos spool up.

That said, acceleration isn’t always brutal, as the electronic stability control (ESC) is often quick to cut power when under full throttle in  first gear. Thankfully, engaging the ESC system’s Sport mode solves this issue.

This behaviour is somewhat ironic as the 4Matic+ system is seemingly never short of grip, with it's working hard to find the axle with the most traction, while torque vectoring and a rear limited-slip differential proportion torque from wheel to wheel.

Regardless, the transmission provides predictably smooth and predominantly timely gear changes, although they’re definitely not dual-clutch quick.

What’s more memorable, though, is the sports exhaust system, which keeps your neighbours relatively sane in the Comfort and Sport drive modes, but will drive them mad in Sport+, with hilarious crackles and pops heard loud and clear on the overrun.

It’s worth noting that while the sports exhaust system can be manually engaged in the Comfort and Sport drive modes via a switch on the centre console, it only makes the V8 rumble grow stronger, with the full effect only unlocked in Sport+.

Of course, there’s more to the GLE63 S experience, like the fact that  it somehow rides like a large SUV yet handles like a sports car.

The suspension’s air springs and adaptive dampers offer up a luxurious ride in the Comfort drive mode, with the GLE63 S wafting along with confidence. Not even its large-diameter alloy wheels pose too much of a threat to this quality on poorer country roads.

The ride is still more than liveable in the Sport drive mode, although the adaptive dampers become a  too firm in Sport+, with the ride becoming a little too jittery to be bearable.

Of course, the whole point of the adaptive dampers becoming progressively firmer is to help the GLE63 S handle even better, but the real revelations here are the active anti-roll bars and engine mounts, which effectively limit body roll to such a level that it’s almost imperceptible.

In fact, overall body control is impressive, with the GLE63 S not feeling like the 2.5-tonne-plus behemoth it is. It really has no right to attack corners the way it does, with the coupe feeling a touch tighter than the wagon, thanks to its 60mm-shorter wheelbase.

Further confidence is afforded by the sports brakes, which include 400mm discs with six-piston calipers up front. Yep, they wash away speed with ease, which is exactly what you’d hope for.

Also key to the handling is the electric power steering, which is speed-sensitive and has a variable ratio. It’s really quick in the wagon, and even more so in the coupe, thanks to its more direct tune.

Either way, this set-up is well-weighted in the Comfort drive mode, with plenty of feel and just the right amount of heft. That said, Sport and Sport+ make it gradually heavier, but neither make the driving experience better, so stick with the default setting.

Meanwhile, Noise, Vibration and Harshness (NVH) levels are pretty good, although tyre roar is consistent at highway speeds, while wind whistle is prominent over the side mirrors when travelling above 110km/h.

ANCAP awarded the second-generation GLE range its maximum five-star rating in 2019, meaning the new GLE63 S gets full marks from the independent safety authority.

Advanced driver-assist systems generously extend to autonomous emergency braking with pedestrian and cyclist detection, lane-keep and steering assist (including emergency), adaptive cruise control with stop and go functionality, traffic-sign recognition, driver attention alert, high-beam assist, active blind-spot monitoring and cross-traffic alert, tyre pressure monitoring, hill-descent control, park assist, surround-view cameras and front and rear parking sensors.

Other standard safety equipment includes nine airbags, anti-skid brakes, electronic brake-force distribution and the usual electronic traction and stability control systems.

The MG IM5 Performance is covered by a seven-year/unlimited km warranty, which is a plus, but the catch is it’s conditional on authorised dealer servicing. Go elsewhere and the term drops to a more common five years/unlimited km. The drive battery is covered for eight years/160,000km, which is the norm in the Aussie market

Servicing is required every 12 months or 20,000km with charges averaging $586 per workshop visit for the first five years, which is on the high side for an EV, even at this price point, the average bumped up by a more than $1400 doozy at year four.

MG IM models are sold (with service available) through all of MG’s 100-plus dealerships across the country, so no concerns there.

As with all Mercedes-AMG models, the GLE63 S comes with a five-year/unlimited-kilometre warranty, which currently sets the standard for the premium market. It also comes with five years of roadside assistance.

Better yet, the GLE63 S’s service intervals are relatively long, at every year or 20,000km – whichever comes first.

It’s also available with a five-year/100,000km capped-price-servicing plan, but it costs $4450 in total, or an average of $890 per visit. Yep, the GLE63 S isn’t exactly cheap to maintain, but you expected that.