Mercedes-AMG S63 vs Lexus Gx550

What's the difference?

Both of these vast vehicles are phenomenally comfortable - this is the kind of car that Mercedes does so well, and has done for decades. The S Class is rarely a disappointment but it's difficult to believe that such a big, heavy GT car can also dance the way the S63 does.

The S560 is far more weighted to being a GT - supremely comfortable with that active suspension, a growly, refined V8 and a cabin full of gadgets and comfort. The S63 is altogether more aggressive, to look at and to drive. Lopping the roof off both of them adds weight but, like any cruiser, also puts you out in the sun, the breeze and into your surroundings. Plus, in the case of the S63, you get more exhaust noise.

They're two very different cars and not just because of the engine. After all these years admiring it from afar, the S63 has delivered on my teenage expectations - fast, smooth and utterly mad.

The new Lexus GX 550 Sports Luxury looks fantastic and has enough mod cons to satisfy a family but it’s not as luxurious as you’d expect from a premium brand and the fuel economy and driving range will turn off some. But if you’re still interested, there’s a lot here that will make you happy and it’s one of the smoothest 4WDs I’ve driven.

The S Class Coupe is obviously related to the sedan but manages a svelte appearance. Slimmer hipped and with a more Coke-bottle shape, the Coupe - if you squint a bit - has a bit of the classic old pagoda about it. Obviously you can't do pillars that slim anymore, but the glass roof takes away some of the visual weight inside and out. 

The cabriolet's roof is nicely integrated and looks good when it's  up, which isn't always the case.

They all look long, though. It's obvious to see why the cars all run on 20-inch wheels - anything smaller would look hilarious.

The cabin is a fairly sensible re-imagining of the E-Class. The big twin-screen layout of the dash and multimedia system seems a bit more at home here. The chintzy Burmester speakers in the doors let down an otherwise classy cabin, which steers clear of otiose vulgarity in looks and materials.

The new GX 550 looks massive and while it shares the same platform as the Toyota LandCruiser 300 series, it doesn't share all of its bulk. They both stand at 1980mm wide but differ on length (5015mm vs 4980mm) and height (1670mm vs 1950mm), respectively.

The new design is fabulously rugged but each body panel looks meticulously crafted and is just the right size. This just means the proportions look right and your eye sort of glides over the big body rather than stopping on any one feature.

But having said that, there are a lot of nice features to focus on, like the long LED headlights and rear strip light, auto-folding side steps, 22-inch alloy wheels and sharply styled rectangular side mirrors.

The tailgate window can also be opened if you need to pop something into the boot but don't want, or have the space, to open the tailgate itself.

The styling takes a minor nose dive once you hit the cabin, though, because it doesn't look as sumptuous as you'd expect in a premium SUV.

I love the utilitarian and military vibe of the vertical dashboard, chunky air vents and relatively small windscreen. It looks great but some trims are plasticky and the touchpoints, while soft, are not Lexus-plush.

However, the technology looks gorgeous with an integrated 14-inch multimedia display and a 12.3-inch digital instrument cluster. The fixed sunroof with its two settings (clear or opaque) is also a lovely feature.

But on a whole, the GX 550's European rivals outclass it with their flashier cabins.

Well look, if you end up in the back of the S Coupe, it's not a riot of space. Obviously it has back seats (the SL doesn't even squeeze a jump seat into its considerable length) but they're for occasional, if luxurious, use.

The boot is a reasonably decent 400 litres, obviously the cabriolet loses a few litres with the roof folded. Front and rear passengers will both enjoy a pair of cupholders and the whopping long doors will each hold a bottle.

The cabin of the new GX 550 is fairly practical with plenty of head- and legroom in each row (yep, even the third!). When you first hop in, it can feel a big snug on elbow-room but this feeling quickly dissipates.

Despite a 215mm ground clearance, access is pretty good for the front and middle rows due to the wide door apertures and side-steps. Third row access is a bit awkward for an adult but my eight-year old loved scampering back there this week.

The electric front seats are comfortable with their extra functions and I like the way the massage feature extends to the seat cushion as it limits fatigue on longer journeys. However, you sit on top of them rather sink into them which makes it feel a little trucky at times.

The wide middle row has a bench seat that will be comfortable for kids but an adult might get a sore behind on a long trip. The transmission tunnel also compromises foot room for adults but the seat is wide enough to make use of all three top-tether anchor points (there are ISOFIX mounts too).

It was a little bit of an effort to lift my big booster seat into the back because the GX 550 sits so tall but otherwise, there's plenty of room around a child seat for them not to feel like a sardine.

Individual storage is made up of a glove box that fits an owner's manual, a small shelf in the dashboard and a middle console that doubles as a cool box (mini fridge) and can fit up to four cans or bottles in it.

Each row gets four drinkholders and two USB-C ports but the front also enjoys a 12-volt socket and wireless charging pad. There's a 220V domestic plug port in the boot for larger appliances, too.

It's sometimes awkward to use the wireless charging pad because it's easy for your phone to slide around on it and it quite often disengaged from charging.

My son enjoyed all of the other amenities in the middle row, like the reading lights, climate control, two USB-C ports and retractable sunblinds and I applaud carmakers when they position rear directional air vents in the pillars and/or roof. It just makes it so much easier to cool down sweaty kids!

The 14-inch multimedia display has clear graphics and a responsive touchscreen. The layout is easy enough to get used to after spending some time with it and the sat nav is simple to use.

I like that the sat nav directions can be pulled into the 12.3-inch digital instrument cluster and head-up display.

There is a Lexus connected services app, which you get a three-year subscription to. It's easy to connect to the wireless Apple CarPlay and there is also wireless Android Auto.

The system also has Bluetooth and digital radio, which is a delight to use through the 21-speaker Mark Levinson sound system.

The cabin is rounded out by the well-shaped boot which has a massive 1063L of capacity when the third-row is folded. That's been more than enough for my family's needs this week and my German Shepherd was pretty comfy back there, too. The powered tailgate has a kick-function and there is a full-size spare wheel underneath the car.

The Lexus GX 550 shares the same platform as the recently introduced Toyota Prado but both models are now based on the same 'body-on-frame' platform shared by the beastie Toyota LandCruiser 300 Series. So it's bigger and features a more rigid chassis than before.

Surprisingly, that hasn't translated to a massive price tag for the GX 550 and you can pick up the flagship grade on test for this review for $128,200, MSRP.

Which sounds inexpensive when you compare it to the BMW X7 xDrive 40i M Sport which is priced from $171,300 MSRP but the Land Rover Defender 110 P400 X-Dynamic HSE is a lot closer at $128,815 MSRP.

The only issue here is that shared platform, because while they don't share the same powertrain, the flagship Toyota Prado Kakadu ($99,990 MSRP) is still almost $30K more affordable and boasts a similar equipment list. So, ask yourself, is it the brand and engine you're after or the new good looks?

The standard equipment is well-rounded with a 14-inch touchscreen media display with satellite navigation and wireless Apple CarPlay and Android Auto.

A fully digital 12.3-inch instrument cluster, colour head-up display, three-zone climate control and a 21-speaker Mark Levinson sound system round out multimedia requirements.

Other technology includes a digital rear view mirror, two USB-C ports in each row, a 12-volt socket, a 220-volt domestic outlet and a wireless charging pad.

There are two particularly handy features for families, the 'cool box' (basically a mini fridge) middle console and rear retractable sun-blinds.

The fixed panoramic sunroof features two settings allowing you to make it clear or opaque. The electric front seats feature heat, ventilation and massage functions and the rear outboard seats are heated as well. The third row electrically adjusts and there are multiple buttons throughout the car to access this feature.

Upgraded leather-accented upholstery is standard in the flagship grade and is available in three combinations. The Sports Luxury also features 22-inch alloy wheels, a full-size spare wheel and a powered tailgate with kick-function.

All four coupes and cabriolets ship with Daimler's formidable 4.0-litre twin-turbo V8. The S560 scores 345kW/700Nm to drive the rear wheels through Benz's own nine-speed automatic. With all of that available, the S560 will crack the ton in 4.6 seconds and make a wonderful racket on the way.

Moving on to the S63, the same engine delivers a massive 450kW/900Nm. The run from 0-100km/h is dispatched in just 3.5 seconds and if I thought the S560 made a good noise, the S63 with its standard sports exhaust makes a better one. Again, Mercedes' nine-speeder is along for the ride.

All GX 550 grades share the same 3.5L V6 twin turbo-petrol engine which produces up to 260kW of power and 650Nm of torque.

This 4WD has high- and low-gearing, as well as a bunch of driving modes to suit most occasions, like 'Eco', 'Comfort', 'Sport' and 'Sport+'.

The 10-speed automatic transmission shifts through its gears smoothly and it always feels like it's engaged in the right gear. Which isn't always the case for a big SUV!

The Sports Luxury is fitted with a towing hitch and cover but unlike the base Sports grade which has a 3.5-tonne braked towing capacity, this model only has a 3130kg capacity which might not appeal to families with big toys to tow. 

The lower-powered 560 drinks 98RON at the rate of 8.5L/100km for the coupe and 9.9L/100km for the heavier cabriolet.

The S63 ups the ante with 9.9L/100km for the coupe and an identical 9.9L/100km for the cab.

Our launch program contained some...er...spirited driving, which would explain the mid to high-teens fuel figures.

I didn’t have high hopes for fuel economy because the official combined (urban/extra-urban cycle figure is a hefty 12.3L/100km but after mostly open-road driving, with some urban stuff mixed in, my real-world average came in at 11.8L.100km! This figure is based on my actual km travelled (358km) and litres of fuel used (42.41L).

While I’m surprised by the fuel usage result, I wouldn’t say this car has good fuel economy compared to its diesel-powered counterparts but it’s not terrible!

The GX 550 has a relatively small fuel tank compared to its Toyota cousins at 80L and based on the combined fuel cycle, you’ll get a theoretical driving range of up to 650km.

Not all that great. Not for a big family mover and not if you’re typically driving in the city, where fuel usage will be a lot higher.

The GX 550 only accepts premium unleaded petrol (95 RON), too.

Let's start with the S560. That smooth V8 rumble is all you'll ever hear if you just slot into drive and go for a leisurely spin. The nine-speed automatic continues to be a revelation to me - in the GLC63 it's good and here, once again, it's excellent, finding the right gear for the occasion and riding the fat torque curve. Other nine-speed autos are not very good at all.

The test route for the S560 played to the strengths of the car. It had some lovely winding roads, which brought the trick suspension into focus - the Magic Body Control with curve function is hilarious. While the active suspension works hard at all times to ensure the ride is smooth and drama free, the Curve mode (no, really) actually leans the car into corners.

Those of you who remember the video game Wipeout 2097 will be big fans of Curve mode. As you approach a corner, you turn the wheel and then the car leans into the bend. This isn't active damping reading the road, it's the outside suspension lifting the car and the inside lowering it, so the car feels like it's gliding, like a hovercar. It's wild but oddly calming. Mercedes reckons it's great for those who get car sick. As I didn't have my wife on hand to test this theory - she chucks at the first sign of a corner - I couldn't verify this claim. That will have to wait.

The S63 AMG is a completely different proposition. The air suspension is more than up to the job of helping smother the effects of the car's considerable weight, meaning that no matter what you're up to, the car feels reasonably light on its feet. It never feels small, though, commanding the respect of the driver and plenty of space from other road users.

And boy, do you need some space if you kick the S63 into Sport mode. In true AMG style, the electronic reins relax and the big luxury coupe cheerfully kicks off. The tail will wriggle under an unsympathetic right foot, that signature V8 roar, crackle and hiss filling your ears. The S63 is always the harder-feeling car, but it delivers with a more sporting drive than the S560.

Being the generous soul I am, I volunteered to return the S63 to its home for the evening rather than consign it to the back of a truck. On the back roads I took to reach the highway, it was rock solid - fast, predictable and a lot of fun. Once I found the boring straight bits, it turned into a supremely comfortable cruiser, ticking along in ninth at the legal limit (and being Melbourne, it was very much the legal limit), dispatching overtaking with barely a flex of a toe. 

The active cruise took the stress of keeping away from the State Revenue Office's clutches while being quiet and utterly pleasant.

Oh my goodness the Sports Luxury is a masterclass on 4WD refinement! You never feel the bulk or weight of this massive SUV when you’re driving it. The power delivery is effortless and there’s lots of grunt available when you hit hills.

The handling is also very good with responsive steering and enough road feedback as a driver to make you feel comfortable with what the car is doing. There is some roll in corners but it can tackle more corners at speed than I thought it would. 

The high driving position makes me feel like I can see a long way ahead yet while visibility is mostly good, it can be compromised when you have the side window shades and the third row headrests up. Which is why I love the digital rear view mirror.

Overall, ride comfort is good with forgiving suspension and low cabin noise, even at higher speeds. It’s pretty easy to chat with all rows and there’s not a lot of engine noise which adds to the refinement. I do like hearing a V6 rumble but that’s just a personal preference. 

I was a little worried about hitting my local Westfield car park but this is a nimble SUV to manoeuvre and parking it is a breeze with the 360-degree camera system and parking sensors. 

The new GX 550 hasn’t been tested by ANCAP and is unrated but its cousin, the Toyota Prado, which shares the same platform just achieved a maximum five-star rating from assessment in 2024. It's fair to expect a good result for this model.

Overall, the Sports Luxury has a long list of standard safety equipment and features nine airbags which is good for a family SUV. 

Safety equipment includes adaptive cruise control, lane departure alert, lane keeping aid, traffic sign recognition, emergency steering assist, driver monitoring, safe exit assist, emergency call functionality, blind-spot monitoring, rear cross-traffic alert and tyre pressure monitoring.

The GX 550 has autonomous emergency braking (AEB) with pedestrian, cyclist, motorcyclist and junction turning assist.

Mercedes offers a three-year/unlimited-kilometre warranty with roadside assist for the duration.

The company also offers both service plans (where you pay up-front as part of the vehicle purchase) and capped-price servicing on the coupes. Servicing over three years is in the order $2500.

Lexus offers the GX 550 with a five-year/unlimited km warranty, which is fairly standard compared to its Euro rivals.

You get five years capped-priced servicing which costs $5950 but the servicing schedule is a bit of a bear at every six months or 10,000km, whichever occurs first.