Lexus RX350 vs Mercedes-Benz G63

What's the difference?

The RX is a big SUV that doesn't always look, or drive, like one, and – in 500h guise especially – can put a smile on a driver's face, too.

Gone are the cabin quirks and the polarising design elements (well, mostly...), and in their place you'll find a solid, premium-feeling family offering without much in the way of drawbacks.

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

The Mercedes-AMG G 63 isn't for shrinking violets. It's bold, fast, and loud, and in second-generation form massively improved dynamically and technically. It's a lot of money, but there's a lot to love, and here's hoping it stays around for decades to come.

Honestly, the Lexus RX looks far more powerful, and cohesive, in the metal than it does in some photos, and in the right colour (we're fond on the deep black or the copper-rose hues), it looks downright fetching.

That Predator-shaped front-end is massive, but the way the Spindle grille kind of bleeds in the body work at the nose of the vehicle is a neat trick, and the whole design ethos gives the RX a sportier, more modern, and more intimidating, energy from almost every angle.

Perhaps the most clever element though is the wave-like design piece that links the rear window with the boot, somehow managing to shrink almost-five-metre SUV (visually, at least), and leaving the RX looking more sporty than hulking.

The door handles are cool, too. They’re fixed, and you just touch them to open the door, with a similar system used once inside to get out again.

Inside, Lexus has gone for a clean, modern-feeling space, and, thankfully, there isn't a Remote Touch trackpad in sight. Instead, you can choose between two screen sizes – 9.8- or 14.0-inch – which kind of dominate the dash, while the air-con controls are digital and interactive, too.

It must be said, though, some interior treatments feel far more special than others, and while Lexus in Australia isn't spilling on specifics for our market just yet, the top-spec models will almost certainly feel more plush than the cheaper ones.

The original (W460) G-Glass, then known as the G-Wagen (or Geländewagen for cross-country vehicle), was launched in 1979 as an ultra-capable off-roader, soon favoured by armies the world over. Arriving here in 1982, its distinctive, slab-sided form remained unchanged over the best part of four decades.

At close to 4.8m nose-to-tail, more than 1.8m across, and a bit over 1.9m tall, the G 63 is now longer (+110mm), wider (+106mm), and fractionally lower overall (-13mm), but still pulls off a convincing impersonation of a bread box.

Merc-AMG confidently quotes a drag coefficient (Cd) of 0.55 for the G 63, which isn't as bad as a brick (around 2.0… I Googled it) although it is in the same league as a heavy truck.

But it's the car's unique, upright stance, complete with pumped wheelarches and old-school flat glass, that sets it apart and draws people in. Looking more like a take-no-prisoners, functional device than a luxury cruiser, I can assure you it attracts as many admiring looks and comments as a low-flying supercar wedge.

The new-gen G 63 features AMG's vertically slatted 'Panamericana' grille, and our test example was fitted with the optional 'Night Package' ($5900) adding a range of dark exterior details including tinted indicator lenses, dark tinted glass, black exterior mirror shells and spare wheel ring, other black trim pieces and painted areas, as well as 22-inch AMG forged alloy rims.

Also worth noting, Merc has retained the G-Class's solid metal door handles, complete with the mechanism's unmistakable 'click-clack' opening and closing sound. Nice touch.

Inside, the biggest change is the upgrade from a conventional dual-gauge instrument cluster and central media stack to a pair of 12.3-inch digital screens, forming a sleek widescreen display, and bringing the G 63 in line with other recent Merc offerings.

Similarly, the gearshift moves from a traditional console-mounted set-up to Merc's 'Direct Select' lever on the steering column (exactly where the indicator stalk is located in 90 per cent of right-hand drive cars).  And the standard flat-bottom, leather-trimmed 'AMG Performance' steering wheel is a racy addition.

Like the exterior door handles, another tip of the hat to the car's heritage is retention of the horizontal grab handle ahead of the front passenger on the dash above the glove box. Nice to have something to hold on to if the going gets rough.

The entire RX range now rides on Lexus' GA-K platform, which is lighter (-40kg), more rigid, and offers a lower centre of gravity (-15mm) than the model it replaces.

The RX is wider (+25mm to 1920mm), lower (-10mm to 1695mm), but no longer (still 4890mm) than the outgoing model. But Lexus has lengthened the wheelbase (+60mm to 2850mm) to earn some extra backseat space for rear riders.

And it must be said, there is lots of room for backseat riders. Sitting behind my own 175cm driving position I had more than enough knee room, and enough head room, and a general feeling of airy spaciousness.

Elsewhere you get the usual practicality perks, with two cupholders up front, two more in the pull-down seat divider that splits the rear seat, and there are two ISOFIX attachment points in the back seat, too.

Charging is handled by a four USB ports, and depending on the trim/spec balance Lexus in Australia shoots for, you should at least find vents with temp controls for backseat riders, too.

Lexus is yet to confirm the luggage space specs for the new RX, but given it’s only being offered with five seats, and that there’s been no change to the vehicle’s length, you can expect a fair bit of room for bags in its auto-opening boot.

The G-Class has never been a particularly squeezy proposition for passengers or cargo, but an extra 40mm in the wheelbase adds even more breathing space.

Getting in is the first step, and it's a big one. At 183cm tall, in an athletic mood, I could grab the A-pillar and swing up into the driver's seat in one vaguely respectable movement.

But, those side steps aren't just for show, and at the end of a long day provide a handy staging camp between terra firma and the lofty pilot's chair.

Once on-board there's plenty of room up front, with adequate storage including a bin between the seats (now with a double door opening rather than a single hinged lid), a modest glove box, oddments space and two cupholders in the centre console, and bins with space for bottles in the doors.

There's a 12-volt power outlet in the front, second row and cargo area, while there are two USB ports in the centre console bin and a charging USB port in the second row.

In the back I could have donned a dusty Akubra and still had headroom to spare, with generous foot room, and a substantial gap between my knees and the driver's seat (set to my position).

A fold-down armrest incorporates a pair of cupholders (as well as a through-port to the cargo space for long items) and there are map pockets on the front seat backs as well as space for bottles in the doors. Two adjustable air vents in the rear of the front centre console, and another pair in the B-pillars also provide climate-controlled air to those in the rear.

With the rear seats upright boot volume is quoted at 454 litres (VDA); enough to easily swallow our three-piece hard suitcase set (35, 68 and 105 litres) or the CarsGuide pram, or a largest-suitcase-and-pram combo.

There are tie-down shackles in each corner of the floor, usefully bright lighting, a netted storage area on the passenger side (containing five fluorescent emergency vests), and folding the 60/40 split rear seat liberates even more space.

Unfortunately, gaining access to that load space is fraught with compromise. First, the single-piece rear door hinges vertically and opens from right to left. No problem when you've nosed into a shopping centre space, but not so great when you're parking nose-to-tail on the left-hand side of the road.

That means you typically have a small space between you and the car behind to get the door open, and when it is at 90 degrees, you're blocked from unloading things onto the footpath until you've shut the door.

As well as that, the door has a full-size spare (alloy) wheel and tyre attached to it. Good because a full-size spare is welcome, and bad because it makes the already bulky door even heavier.

Those keen on towing things will be pleased to hear the G 63 is rated to haul up to 3.5 tonnes of braked trailer and 750kg unbraked.

Okay, you're laying down a quarter of a million bucks ($247,329 before on-road costs) and it's fair to expect some serious tech and standard equipment to keep you feeling warm and fuzzy after you're finished impressing friends and family with the G 63's howling acceleration.

For a start, there's a bunch of leading-edge safety tech on-board (detailed in the safety section below), and as expected that substantial cost-of-entry brings an extensive list of luxury features.

We've touched on the twin 12.3-inch 'Widescreen Cockpit', and available media includes digital radio and TV tuner, internet connectivity and 3D nav (with dynamic route guidance), as well as smartphone integration with Apple CarPlay and Android Auto.

Audio is a thumping 15-speaker, and 590-watt Burmester surround sound system, and the ambient lighting set-up offers a choice of 64 colours.

Also included are 'Multibeam' LED headlights, 'AMG Ride Control' adaptive damping, a 'Parking Package' with 'Active Parking Assist' and 360 camera, a sliding glass sunroof (with tilt function), the selectable AMG sports exhaust system, keyless entry and start, the AMG Performance steering wheel (trimmed in nappa leather), and 21-inch AMG '5-Twin spoke' alloy wheels.

Then there are the three 100 per cent differential locks (plus an 'off-road information centre'), electronically adjustable front seats (ventilated front and heated front and outer rear), steering column and mirrors (with memory function), three-zone climate control, nappa leather upholstery, a leather-finished dashboard with open-pore ash wood trim, a 'Dinamica' microfibre roof liner, and an AMG-specific IWC design analogue clock. Plus, the 'Dynamic Select' system enables a choice of pre-set driving profiles or individual settings.

The optional 'Exclusive Interior Plus Package' ($10,300) fitted to 'our' car adds deluxe nappa hide on the dashboard, door centre panels and grab handle, as well as a diamond quilted treatment on the seat centres, a black 'Dinamica' roof liner, velour floor mats (with edging in nappa leather), a frameless interior mirror and air vents in 'Silvershadow'.

On top of that the test vehicle was optioned with the 'Night Package' ($5900) detailed in the Design section, and Designo 'diamond white bright' paint ($5900) for a manufacturer's recommended list price (MRLP) of $269,429.

That puts the G 63 in the same price and equipment ballpark as the supercharged V8 Range Rover Autobiography ($268,900), twin-turbo V8 Porsche Cayenne Turbo ($239,400), and its Mercedes-AMG GLS 63 sibling ($221,729), powered by a version of the 5.5-litre twin-turbo V8 used in the first-gen G 63.

An impressive trio of alternatives, but in reality the idiosyncratic G 63 doesn't have any direct competitors, and for those who give in to the pull of its powerful tractor beams value-for-money becomes a uniquely personal concept.

Let’s start with what we’re not getting at launch. Internationally, there's a new plug-in hybrid variant that pairs a 227kW hybrid system with a 18.1kWh lithium-ion battery for an EV driving range of more than 65kms, but fight though Lexus in Australia did, it couldn't secure the model for our market at launch. It wants it though, and badly. So watch this space. 

Instead we get three options, including the RX 350h, which pairs a 2.5-litre petrol engine with Lexus' existing hybrid system to produce a total 180kW and 316Nm. It's paired with a constantly variable transmission and will be offered in two- or all-wheel drive.

There’s also a turbocharged 2.4-litre petrol engine on offer in the RX 350, good for 205kW and 430Nm, and paired with an eight speed automatic and AWD.

But the powertrain I really, really like lives in the RX 500h F Performance, and pairs a 2.4-litre turbocharged petrol engine with an electric motor up front, and a second at the rear axle, for a total of 273kW and 551Nm.

The all-new hybrid system has been designed with turbocharged engines in mind, and features a single electric motor at the front, and a bigger rear motor, with the latter able to provide real driving power to the rear tyres - and contribute to a sprint to 100km/h of just 5.9secs.

Lexus calls it an 'eAxle' motor, and it can deliver some 76kW to the rear tyres. It pairs with a 'DIRECT4' all-wheel drive system which the brand says improves "handling, controllability, and feel."

Fitting, then, that it features on the RX 500h F Performance, which also introduces a new go-fast tier for the Lexus brand (though one you can expect to see more frequently in the near future), and which sits between the existing F Sport and the top-tier, full-fat F models.

The brand says things like bigger brakes, performance components and the highest power outputs will be reserved for the F Performance models. And so it is with the RX 500h F Performance, which welcomes six-piston front brakes, adaptive variable suspension, dynamic rear steering and 21-inch wheels.

The G 63's 4.0-litre (M177) all-alloy V8 is closed deck design using direct-injection and a pair of twin-scroll turbos to produce 430kW at 6000rpm and no less than 850Nm from 2500-3500rpm. That's 10kW/90Nm more than the 5.5-litre twin-turbo V8 it replaces!

To improve throttle response and optimise efficiency, the turbos are located inside the engine's 'V', improving air flow and shortening the distance from the exhaust side to the turbos, and in turn, from the turbos to the inlet side.

And the housings on the twin-scroll turbos are divided into two parallel flow channels connecting with separate ducts in the exhaust manifold, allowing fine management of the exhaust gas coming in and pressure going out. Result is more torque and even better response times.

Drive goes to all four wheels via a new 'AMG Speedshift' nine-speed, dual-clutch auto (replacing the previous seven-speed auto transmission) with paddle shifters and a multiple downshift function which will go to the lowest ratio possible as you keep squeezing the shift paddle.

The 'AMG Performance 4Matic' all wheel drive system is front/rear biased 40/60 (50/50 in the previous model), although if you want to head off-highway the G 63 still features three 100 per cent diff locks and low-range off-road gear reduction.

Let’s start with the pure-petrol RX 350, which will sip a claimed 8.8 litres per hundred kilometres on the combined cycle, and will demand premium petrol. The RX 350h is more fuel efficient, demanding 6.4 to 6.7 litres per hundred kilometres on the combined cycle.

But the most impressive is the RX 500h, which Lexus says will need 8.2 to 8.5 litres per hundred kilometres — making it more efficient than the petrol-powered RX 350, despite producing an extra 68 kilowatts of power and 121 newton metres of torque.

Claimed fuel economy for the combined (ADR 81/02 - urban, extra-urban) cycle is 13.1L/100km, with the 4.0-litre, twin-turbo V8 emitting 299g/km of CO2 in the process.

Despite the fact cylinder management tech means the engine will run on four cylinders under light load, and start-stop (with 'glide mode') is standard, we managed 16.7L/100km (measured at the bowser) over a mix of city, suburban and freeway running. To be expected for such a big bus, especially one that constantly tempts you into squeezing the throttle just to hear the exhaust bellow.

Minimum fuel requirement is 98 RON premium unleaded, and you'll need 100 litres of it to fill the tank.

Right, let’s cut to the chase here. I like the way the all-new RX family drives, pretty much across the board. If that’s all the information you want or need, feel free to check out here and move on to the next sub-heading.

Still here? Ok, then let’s go a little deeper.

None of the powertrains on offer feel under-powered in the RX range, which is a good start, but they all do their jobs a little differently. 

The RX 350 is probably the most familiar, with a traditional automatic and that well-known petrol-powered punch. It’s not the most powerful engine on offer here, but it’s more than enough to get the RX up and moving — but, for mine, it can feel a little thrashy (or like it’s straining a little too hard), when you really start to push it, but such is the price you pay for a four-cylinder engine pushing a large SUV.

Next up is the RX 350h, which Lexus reckons will be the best-selling model in Australia. Lexus and Toyota have been doing hybrid powertrains for some time now, and the system fitted to the new RX is predictably solid-feeling, though it too has its drawbacks – namely that the constantly variable transmission can drone on and on under constant acceleration, and even the commendably insulated cabin can’t block it out completely.

So if this is a Goldilocks’ scenario, then the just right has to be the RX 500h, which blends its powerful powertrain with a traditional-feeling automatic to deliver plenty of performance and a tight, engaging drive experience that makes it feel as though the big SUV is somehow shrinking around you from behind the wheel, courtesy of the best performance kit (brakes, adaptive suspension, etc).

But to be honest, no matter the RX, the thing that really stands out here is its on-road dynamics. The car doesn’t really wobble about, there’s not much in the way of body roll, and it feels tight and confidence inspiring, no matter the model - but especially the rear-wheel-steering equipped 500h.

The RX also does a commendable job of locking the outside world outside of the cabin. Where you want it to be a calm and sedate family hauler, it can be that. But it can also put a smile on your face on the right road, too.

And that, I think, is something to be celebrated. And also not something we’ve come to associate with Lexus over the years. But that’s now beginning to change. Long live F Sport Performance, then.

Let's cut to the chase. The G 63's pure grunt overpowers its challenging aero profile to thrust this boom box on wheels from 0-100km/h in a claimed 4.5 seconds. And believe it or not, despite its greater length and width, it has enough power to punch a 240km/h hole in the air (maximum velocity is limited to 220km/h if you choose not to opt for the 'AMG Driver's Package').

The new electronic architecture brings with it the latest version of Merc's 'Dynamic Select' system with five driving modes adjusting the engine, transmission, suspension, steering and assistance systems right up to maximum attack Sport+ mode.

All 850Nm of peak torque is available between 2500-3500rpm and pinning the throttle anywhere in that band feels like lining up a runway and preparing to rotate for take-off.

The two-stage exhaust flap arrangement allows you to turn the noise up from growl to roar even at modest around town speeds, and the nine-speed transmission is sharp and positive, with the multiple downshift function (in manual mode) hilariously good fun.

The racy AMG sports seats are as grippy as they are comfortable, and the fat 295/40 Goodyear Eagle F1 rubber, wrapped around the optional 22-inch forged alloys, does a good job of keeping all that mass and momentum in control as the high riding G 63 careens around corners.

And speaking of mass, the job of hauling it from warp speed to rest sits with big ventilated discs all around (cross-drilled 400mm front/370mm rear), clamped by monster six piston calipers at the front and single piston at the back. They're progressive and reassuringly powerful.

So, the performance is as dramatic as ever, but when I think of previous Merc-AMG G-Class offerings, two main shortcomings come to mind... steering and ride.

The steering was like a laggy mouse, with a few beats separating input at the wheel from response at the front treads. And the damping came up short, with a bouncy ride par for the course.

Still sitting on a ladder-type frame, the new G's suspension was developed by Mercedes-Benz and Mercedes-AMG. And finally, it has a decent double-wishbone independent front-end, with a rigid axle at the rear and coil springs all around. Plus, a strut tower brace, Merc-AMG calls it a 'suspension bridge', now connects the front strut towers, increasing torsional rigidity.

Ride comfort, especially in the most compliant 'Ride Control' suspension setting and riding on the big 22s, is massively better. It's no limo. You'll still feel jittering over higher frequency imperfections. But it's way, way ahead of the first-gen version.

The steering system changes from a recirculating ball to rack and pinion, and is now variable ratio with electro-mechanical rather than purely hydraulic assistance. And it's also much improved. We're not talking about a Lotus Elise-style connection with the road, but the steering is clearly more predictable and responsive.

One thing that hasn't changed is an ocean liner-worthy, 13.6m turning circle. You'll need to plan ahead for U-turns and reverse parks, but enough parking cameras (including surround view) to please Cecil B DeMille are on hand to help.

It's like a whole new world with a familiar cover wrapped around a markedly improved package. But (there must be a but) visibility is still compromised by thick window and door pillars, and despite the new dash layout ergonomic efficiency is patchy, with some switches and knobs located in relatively awkward positions.

As mentioned earlier the G 63 features three 100 per cent diff locks and low-range off-road gear reduction. But forget breakover angles and wading depths. This 4x4 seeing off-road action is as likely as an Abbott 2.0 prime ministership.

Suffice it to say, this car wears the 'Schöckl' badge at the base of its B-pillar. And in case you were wondering, Schöckl is a 1445m mountain in Graz, the Austrian city where the G-Class is built (and big Arnie Schwarzenegger was born!).

In the second-gen G-Class's development, prototypes covered roughly 2000km over a five kay trail including gradients of up to 60 per cent and lateral inclines up to 40 per cent. So, despite its irrelevance, the off-highway box is ticked.

The second-gen G 63 hasn't been assessed by ANCAP or Euro NCAP but its new electronic architecture brings the car up to speed on active safety tech, now incorporating 'Distronic' cruise control with 'Active Distance Assist', 'Active Brake Assist', AEB (forward and reverse), 'Active Lane Keeping Assist', 'Blind Spot Assist', 'Adaptive High-Beam Assist', tyre pressure monitoring, and 'Traffic Sign Assist'. Plus, the 'Pre-Safe' system prepares the vehicle and occupants in the face of an inevitable collision.

And once that impact has occurred, you're protected by nine airbags, including rear seat airbags, full-length curtains and a driver's knee bag.

There are three top tether points for child restraints/seats across the back seat, with ISOFIX anchors in the two outer positions.

The Lexus family is covered by a five-year, unlimited-kilometre warranty, which is about bang-on in the premium-vehicle space. 

While servicing details are yet to be confirmed, the previous RX required a trip to the service centre every 12 months or 15,000kms, and it will fall under the brand’s capped-price servicing program, and the Lexus Encore program, which offers all sorts of perks to owners.

Mercedes-Benz (and by extension Mercedes-AMG) offers a three-year/unlimited km warranty with 24 hour 'Road Care' emergency roadside assistance provide for three years.

Servicing is recommended every 12 months/20,000km and a capped price servicing plan is available at Silver and Platinum levels for up to five years/100,000km.