Kia Stonic vs Lexus Rx450H+

What's the difference?

Unlike a lot of rivals in this segment, the Stonic's actually quite a bit of fun to drive, and that alone earns it a tick from me.

Yes, it can feel underpowered in places, especially when you're trying to do high-speed overtakes or if you're on a really engaging road and on and off the accelerator. But just cruising around, the little powertrain gives you plenty to get around the city.

And I guess that is the point. This does feel like a very city-friendly vehicle, even if it is undeniably showing its age in places.

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

Note: The author, Andrew Chesterton, is a co-owner of Smart As Media, a content agency and media distribution service with a number automotive brands among its clients. When producing content for CarsGuide, he does so in accordance with the CarsGuide Editorial Guidelines and Code of Ethics (https://www.carsguide.com.au/ethics), and the views and opinions expressed in this article are solely those of the author.

The new Lexus RX450h+ Sports Luxury is packed with a wealth of premium features and strikes a solid balance between refinement and practicality. There are enough thoughtful touches that make everyday driving a little easier.

You’ll get the most out of the plug-in hybrid powertrain if you’re able to charge it regularly; ideally every day. That might not always be practical for busy people on the go, but overall, the RX450h+ manages to blend efficiency with Lexus’ signature comfort and quality.

I'm not gonna spend too much time on the exterior design, because from most angles it largely looks a lot like a Kia Stonic, right? The big exterior change occurred up front, where the old Kia 'face' was retired, and replaced with an LED-trimmed front-end more in keeping with modern Kia models.

It is a tale of good and bad in the cabin of the Stonic. The good is the fact that it all feels very familiar and very Kia, which isn't a bad thing.

Th bad is some of the door materials aren't just cheap and hard plastic, but they feel a bit flimsy in places as well. Same with the centre console plastics. There are some elements where you could definitely lift up the ambience in the interior.

The RX isn’t breaking new ground with its plug-in hybrid design, but it still delivers that signature Lexus understated refinement.

The strong, flowing body lines, 21-inch alloy wheels and updated 'spindle grille' all give it presence without screaming for attention.

And in a segment where boxy and bulky designs tend to dominate, the RX’s swoopy silhouette helps it stand apart in all the right ways.

Inside, the cabin feels considered and luxurious. There's a heavy use of premium materials, including the leather and suede upholstery, plush soft-touch surfaces and the big, crisp displays that make the space feel modern and high-end.

The panoramic sunroof brings in loads of natural light, too, which is especially welcome given the dark headliner that might otherwise feel a little heavy.

If I have one gripe, it’s the thin steering wheel, which doesn’t quite match the otherwise solid, tactile feel of the rest of the interior. But overall, the cabin is a space that feels luxurious and well-executed. It's quietly confident, just like the RX.

In the GT-Line trim, you get the twin screen setup, which looks sharp, and I do like Kia's multi-function control bar, which takes care of things like navigation and media on the one digital screen.

It really is feeling a little bit old school in places. There's no wireless phone mirroring, for example, so you need to plug in. And even then you need to plug in with a USB-A rather than a USB-C, despite having both plugs at your disposal.

The other thing is that the GT-Line is almost $36k before on-road costs. And there are places where it just doesn't feel like that much money.

It's a case of what you see is what you get in the back seat of the Stonic. And what you see is... not that much.

There are two USB-C ports in the more expensive trims. There are bottle holders in each of the doors, but no cup holders, and no pull-down seat divider. It is a fairly sparse back seat experience.

What you do get, however, is the luxury of space. Sitting behind my own 175cm driving position, I had absolutely no problem with knee room and no problem with head room. In fact, even as an almost full-size adult, I reckon I could sit back there pretty comfortably, even on longer road trips.

The big news is the addition of a 48-volt mild hybrid system, and that 48-volt battery is under the boot floor. But because it's hidden under a flat partition, it actually doesn't impact boot space.

Kia is still claiming 352 litres with the rear seats in place and 1155 litres with the rear seats folded flat. You do, however, miss out on some under-boot storage. And there's no spare wheel to speak of, just a tyre repair kit.

The RX cabin is thoughtfully laid out and impressively practical, with a premium feel that doesn’t come at the cost of everyday usability.

Up front, there’s plenty of space for driver and passenger, yet the stepped dash design brings a sense of intimacy. The electric front seats are seriously comfortable, with four-way lumbar support and extra adjustment functions that make this an easy choice for long drives.

Storage options are generous, too. There’s a clever dual-opening centre console, large glove box, multiple phone-sized shelves, map pockets and a couple of cup- and drink holders in each row.

Charging is taken care of by four USB-C ports, one USB-A port and a wireless charging pad.

Tech is up-to-date and well-integrated. The upgraded 14-inch media display looks crisp, supports wireless Apple CarPlay and Android Auto, and is paired with a revamped 12.3-inch digital instrument cluster and a colour head-up display.

The cluster’s new layout is modern and much easier to read than the previous offering. The digital rear view mirror also earns its keep when the cabin’s packed with passengers or gear.

One of my favourite touches? The seat controls on the side of the front passenger seat. It makes quick work of moving the seat forward, especially helpful when you’ve got a kid clambering in with a school bag full of projects.

Access to the rear row is easy, but the stadium-style seating, where you're perched noticeably higher than those in the front, won’t be for everyone.

That said, the rear seats are plush and padded, though they lack side bolsters, which rear passengers might notice during cornering.

Legroom is generous and the hardened kickplates are a dream to clean when your child’s treating the seatbacks like a climbing wall.

My eight-year old gives the back seat a glowing review, thanks to its creature comforts, including rear climate control, directional air vents, seat heating/ventilation on the outboard seats, two USB-C ports and retractable sun-blinds, which are a crowd favourite in our household.

There are three top-tether anchor points, and the bench is wide enough to fit three child seats, though bulky booster seats might be tricky due to the raised seating height.

At the back, the boot is well set up for families, offering electrically folding rear seats, a 12-volt socket, flat loading floor, and a hands-free powered tailgate.

Under the floor, there’s a small compartment for your charging cables (Lexus throws in two!) and a usable 612L of capacity when all seats are in use. One downside, though, is the lack of a spare tyre as you just get a tyre repair/inflation kit.

There are four variants in the RX range, and we’re testing the 450h+ Sports Luxury AWD, which sits just below the flagship and packs in plenty of premium kit for its $123,500, before on-road costs, price tag.

That makes it slightly more affordable than its main PHEV rivals; the BMW X5 xDrive50e (from $125,885 MSRP) and the Volvo XC90 Ultra (from $124,466 MSRP).

The Volvo does offer seven seats to the Lexus’ five, which may matter for larger families, and both rivals also outdo the RX on electric-only driving range - 65km in the RX compared with 77km in the Volvo XC90 and a generous 101km in the BMW X5.

Still, the RX fights back with a seriously stacked features list. Highlights include a panoramic sunroof, 10-way powered front seats with heating and ventilation, electrically folding rear seats (also heated and ventilated in the outboard positions), and a heated, power-adjustable steering wheel. Sound is taken care of by a premium 21-speaker Mark Levinson surround system.

Technology has had a solid upgrade with the 14-inch touchscreen multimedia display, 12.3-inch digital instrument cluster, digital rearview mirror, colour head-up display, live traffic navigation, wireless Apple CarPlay and Android Auto, 4G connectivity, four USB-C ports, one USB-A port and a fast wireless charging pad.

There’s also access to the 'Lexus Connected Services' app, allowing you to remotely lock or unlock the vehicle, pre-set the cabin temperature via three-zone climate control, configure driver profiles and even use your phone as a digital key.

Practical features include keyless entry and start, rain-sensing wipers, dusk-sensing LED headlights, rear sun-blinds, intelligent seatbelt reminders for the first two rows, a child presence alert and a hands-free powered tailgate. However, due to the plug-in hybrid system there’s no spare tyre, just a tyre repair kit.

All Stonics get the same powertrain. A clever three-cylinder, 1.0-litre turbocharged petrol engine with 48-volt mild hybrid assistance. That means 88kW and 172Nm (up from 74kW). It has a seven-speed dual-clutch transmission.

We don’t have an official zero-to-100km/h time, but I’m estimating in excess of 10 seconds.

Under the bonnet the RX450h+ Sports Luxury runs a plug-in hybrid powertrain that pairs a 2.5-litre four-cylinder petrol engine with a CVT auto and dual electric motors - one on each axle. Together, they produce a total of 227kW of power, though Lexus doesn’t quote a combined torque figure.

Still, it’s quick off the mark for a large SUV, with a 0-100km/h time of 6.5 seconds. There’s more than enough grunt for daily driving and overtaking, even if it doesn’t quite match the outright power of its key PHEV rivals.

The 48-volt system helps drop both fuel use and C02 emissions, with the Stonic pegged at 5.0L/100kms on the combined cycle and 116g/km for emissions, both of which are lower numbers than the last model.

The Stonic’s 45-litre tank could theoretically deliver a circa-900km driving range.

The plug-in hybrid system brings solid efficiency, with claimed fuel use of just 1.3L/100km. In real-world conditions (mostly urban driving with regular recharging) I managed a respectable 4.8L/100km, which makes a strong case for the hybrid set-up.

The fuel tank holds 55 litres and it's worth noting Lexus recommends using a minimum of 95 RON unleaded petrol to fill it.

Using our real-world economy figure you can expect a range in excess of 1100km between fills.

The RX450h+ is fitted with a relatively small 18.1kWh lithium-ion battery, supporting an NEDC electric-only range of up to 65km.

While that’s fine for short daily trips, it’s shorter than you'd ideally want in a family SUV of this size and it lags behind rivals like the BMW X5 and Volvo XC90 in this department.

Charging is simple enough. The RX uses a Type 2 charging port and accepts up to 7.0kW on AC power, which means a full charge takes around 7.5 hours, perfect for overnight top-ups. Lexus also includes an at-home charging cable and second adapter cable as standard, which is a thoughtful touch.

It is a really interesting drive proposition, this Stonic.

First and foremost, it does feel really well sorted in places. The steering has a nice weight to it. It's nice and direct. The ride is comfortable. It can get a little bit crashy over the harsher bumps, which actually isn't all that common in Kia products – like if you hit a cat's eye at speed, for example, you can definitely feel it in the cabin – but generally it's an engaged and comfortable drive.

Similarly, going around corners, even at speed, there's not a huge amount of body roll. The tires grip up pretty well, and it's really not a bad thing to throw around corners.

Where it gets interesting, though, is in its power delivery. At city speeds, so 50 or 60km/h, it's nice and easy and quiet. If you're gentle with the accelerator, and patient, it accrues speed in quite a calm, considered manner, without feeling overly sluggish.

Where it does start to fall apart a little bit, which is when you're at speed, say on a freeway for example, and you pull out to overtake and really plant your foot, and find there's really not a lot there. It can mean overtaking takes a lot longer than you might think. 

If you're on a really challenging road and you're kind of on the gas, on the brakes, on the gas and on the brakes, it can feel a little bit wheezy and uncertain, too, which is no doubt a byproduct of that relatively tiny powertrain.

We're definitely not talking rocket ship acceleration, and nor is it all that quiet in the cabin when you really start to wring its neck, which you will do occasionally.

But I think I've really stepped away from what this vehicle is supposed to be and what it's supposed to do. If you are easy with the accelerator, it can be a really calm, quiet cabin experience. And if you do find yourself on a twisting road, it actually sits and grips better than you might be thinking as well.

But there is no doubt the Stonic shines brightest in the city.

The RX450h+ delivers power that’s pert and prompt, with genuine bursts of acceleration that make driving fun. It’s always ready to go and there's no lag in stop-start traffic - which gives it a lively, dynamic feel around town.

The transition between petrol and electric power is seamless; you hardly notice the switch, which makes for a smooth, refined driving experience. The cabin is impressively quiet, even on the highway, making long trips comfortable and peaceful.

Regenerative braking isn’t adjustable and is subtle enough that many won’t notice it which is likely a plus for fans of traditional internal combustion engines who are making the PHEV leap.

The adaptive variable suspension adds a sporty edge to handling, letting you confidently take corners at speed. There’s some body roll but the RX never feels top-heavy or unsettled.

The steering carries the weight of the SUV but remains well-balanced and responsive. Overall, it’s a well-tuned machine that’s a pleasure to drive.

Maneuverability is a strong suit, too, thanks to a tight 11.8-metre turning circle and a clear, easy-to-use 360-degree camera system. Parking is easy-as-pie, which a lot of drivers will appreciate.

The RX earned a maximum five-star ANCAP safety rating in 2022, scoring highly across all protection categories: 90 per cent for adult protection, 89 per cent for child protection, 89 per cent for vulnerable road users, and 93 per cent for safety assist systems.

Standard safety gear includes eight airbags (dual front, front side, curtains, front centre, and driver’s knee) plus a comprehensive suite of driver aids. Standout features include emergency call functionality, child detection alert, side exit assist, front and rear collision warnings, park assist and emergency steering assist.

Additional tech covers blind-spot monitoring, driver attention monitoring, tyre pressure monitoring, daytime running lights, LED cornering lights, rear cross-traffic alert, lane departure alert, lane keeping assist, traffic sign recognition, and intelligent seatbelt warnings for the front two rows.

Visibility and parking are enhanced by a 360-degree camera system and front/rear parking sensors, while adaptive cruise control adds comfort on longer drives.

The rear seats have two ISOFIX mounts plus three top tether anchors, accommodating child seats safely. Autonomous emergency braking is active from 5.0 to 80km/h for pedestrians, cyclists, and backover and up to 180 km/h for cars.

The Stonic is covered by Kia’s seven-year unlimited-kilometre warranty, with capped-price servicing covering the warranty term.

Servicing is required every 12 months or 10,000kms, and all seven services will set you back $3780 combined.

The RX comes with a five-year, unlimited-kilometre warranty, which matches its key rivals but isn’t exactly class-leading by today’s standards.

Servicing is handled via a capped-price program, with each service costing $695. The intervals are well spaced at every 12 months or 15,000km, whichever comes first.

This Sports Luxury grade also includes a three-year complimentary 'Lexus Encore' membership, granting access to a handy phone app and member benefits at partners like Westfield and Ampol. On top of that, you get 24/7 roadside assistance for added peace of mind.