Lexus RX350L vs Lexus RX450H

What's the difference?

Lexus has seemingly added two extra seats to its RX range without any design or dynamic drawbacks. If you're a fan of the five-seat car, there's little doubt you'll be a fan of this one, too. 

What it will come down to, though, is how often you use the third row of seats, and how big the humans that will be sitting in them in are. If they're for kids or for occasional use, the space will be ample. But if your child has undergone a Tom Hanks in Big-style growth spurt, you will likely find the space back there too tight for everyday use. 

The RX is a little frustrating - it's going after Mercedes and BMW and Audi in a hotly-contested space and falls over in a couple of key areas. The media/sat nav system is hopelessly outdated and the drivetrain fails to deliver a significant performance or fuel benefit (although, given its 2.2 tonnes, perhaps it delivers a miracle).

It does come with a rock-solid, scandal-free reputation, a reputation for spectacular customer service, it has a lovely cabin and it's certainly an individual looker. For plenty of people, that's quite enough.

All the action takes place at the back end here (essentially from the rear wheels back), with Lexus adding 110mm in length to form the RX L, which sits on an identical wheelbase to the five-seat car.

They deserve credit for not making this seven-seat version feel like a behemoth, with the extension in keeping with the style of the five-seat car (same 'floating roof' sitting above a kinked pane of glass), with only the more vertical and extended boot line hinting at the third row inside.

Elsewhere, it’s business as usual for the RX L, with the bigger model sharing the sharply angled body styling, narrow headlights and ferocious-looking grille of the standard RX.

Inside, expect a premium-feel interior, with leather seats in the first and second rows (the third gets the man-made stuff), elegant wood finishing and a sleek and simple dash set-up dominated by a floating screen in its centre.

There's a lot of RX and there's a lot going on in that creased, folded and teased sheetmetal. It's a unique design, with a huge 'spindle grille', big lights and the fast glass both front and rear.

It positively screeches Lexus DNA and was a polarising force on our driveway for the week. Most weren't sure, but knew for certain it was a Lexus.

Aggressively flared wheelarches like this aren't common on SUVs (although the squared-off ones are). It's right up on stilts, but the 20s you find it rolling on help to reduce its visual bulk.

That wacky rear quarter glass reminds me of the BMW i3's but it's a Lexus SUV signature. It's quite striking. Do I like it? Not really, but that's completely subjective. You can tell, though, it's built tight as a drum.

Inside is a bit calmer, beautifully laid-out and built to last. The materials are almost all top notch, with lovely switchgear and the real leather is really nice.

There is absolutely nothing avant-garde in there (apart from maybe the pinstripe effect on the centre console), it's all terribly comfortable and easy on the eye. But not exciting, though not all Lexuses are.

This particular car is very US-centric and, if I may, a particularly sunny and humid part, so it can't be too wacky.

You know how there are some seven-seat SUVs in which, at a pinch, you can squeeze two adults into the third row? Well, the RX L isn't one of them.

For one, climbing over the second row (after pulling a manual handle that Lexus says is quicker than an electric set-up) requires some acrobatics. And once in the seat, my head (I'm 175cm) found itself in an intimate relationship with the roof. My knees were forced into the seat in front, and most worryingly, my presence pushed the second row far enough forward to make that passenger uncomfortable, too. 

Still, how often are you really going to squeeze adults back there? There is certainly enough room for younger kids, or - as I suspect is more likely - for the third row to be used as an in-case-of-emergency option. It can house a child seat, too.

There's not a bad ambiance back there, though, with artificial leather seats, two central cupholders and tri-zone climate with vents and temperature controls. Middle-row riders now get an extra 45mm of forward adjustability (to compensate for the third row), and there are two cupholders hidden in the pull-down seat divider and bottle room in each of the rear doors.

Up front, expect two cupholders, along with a pocket in each door, while the large central storage bin is home to two USB connection points and a power source, the latter matching a second power source underneath the air-conditioning controls. 

And so, to the boot. All three rows in place, you'll find 176 litres of storage to the seat-tops (211 litres to the roof). Lower the third row, and that number climbs to 433 litres. Drop the second and third row, and you'll find 966 litres of storage.

There is plenty of room inside this big unit, which is very welcome. Front seat passengers have lots of storage, such as a deep central bin under the armrest, dual cupholders and big door pockets with bottle holders.

Step into the rear and there is a ton of leg and headroom although the transmission tunnel intrudes slightly for the middle passenger. Chuck them out, drop the armrest and you have two more cupholders and each door has pockets and bottle holders.

The boot is pretty big considering the angle of the rear glass. You start with 453 litres (but an expanse of flat floor), which rises to 924 litres with the split-fold seats down. That seems conservative given just how much space you appear to have.

The RX450h F Sport lightens your bank account of $102,460 before on-road costs, the only hybrid SUV within cooee of this price.

That nets you 20-inch alloys, a 15-speaker stereo, dual-zone climate control, heated and cooled electric front seats, reversing camera, that ever rare CD player, keyless entry and start, a solid safety package, reversing sensors, active cruise control, sat nav, a massive sunroof, auto LED headlights, head-up display, partial leather interior, power tailgate, auto wipers and a space-saver spare.

The Lexus media system is run from the gigantic dash-mounted screen that is shamed only by those massive Tesla units.

Sadly, the joystick-style control remains as does the very confusing software system that is less than delightful to use. It's such a shame that a tech-laden machine is let down by the world's most baffling entertainment system.

Once you get it working and understand it, it's okay, I guess, but several years into this job I still can't easily fathom how it works. And that naff analogue clock...

F Sport cars also pick up adaptive suspension and a several driving modes to liven things up.

There are two engine options on offer here; the V6 of the 350L or the hybrid powertrain of the 450hL.

The six-cylinder petrol engine is good for 216kW at 6300rpm and 358Nm at 4600rpm, sending that power to all four wheels via an eight-speed automatic transmission. 

The hybrid option uses the exact same engine, just with lower outputs of 193kW at 6000rpm and 335Nm at 4600rpm. It's paired with an electric motor that lifts the total output to 230kW. That combination pairs with a CVT auto, sending power to all four wheels. 

Lexus claims identical performance figures for both options, with a 0-100km/h sprint of 8.0 seconds and a top speed of 200km/h.

You can choose three different powertrains in the RX - a 3.5-litre V6, a 2.0-litre turbo four-cylinder, or this one, the 3.5-litre V6 with hybrid.

As a series hybrid it can run for short distances on electric only before firing up the V6 to supply charging and motivation.

The 3.5 produces 193kW/335Nm along with the electric motor. That torque figure seems low and it probably is, but that's a function of the weird way of measuring torque from a hybrid unit. The combined power figure, however, is 230kW.

The hybrid system is hooked up to Lexus' CVT auto and sends power to all four wheels. Lexus says the 450h will complete the sprint from 0-100km/h in 7.7 seconds, which isn't bad for a 2210kg SUV.

The petrol V6 will require a claimed 10.6L per 100km on the combined cycle, with the hybrid predictably performing better, returning 6.0L/100km on the same cycle. Emissions of CO2 are pegged at 234g/km (V6) and 137g/km (hybrid).

The V6-powered RX boasts a 72-litre tank, while the hybrid shaves several of those off, offering 65 litres.

The official combined cycle figure is listed as 5.7L/100km. And, uh, yeah, we didn't get that. I did manage 8.9L/100km over the week, which included a long motorway run from Sydney up to the Blue Mountains (a roughly 160km round trip).

Let’s start with the good news: having admittedly only been behind the wheel for a shortish stretch (and a lot of that was on a freeway) I’ll be damned if I can spot the difference from five- to seven-seater.

Its 110mm longer than the five-seat car, of course, and it's heavier, too. And a more thorough test might well reveal those extra kilograms from behind the wheel. But I suspect you'd have to be truly pushing the RX L around some serious corners to have any chance of noticing.

Keep in mind, this isn't the sportiest option in the segment, and this L version isn’t either. The steering feels a little vague and flat on-centre, and neither engine offers face-peeling acceleration. But the ride is terrific, the cabin is comfortable and polished and both the Luxury and Sport Luxury are ferociously well-equipped. 

We'll wait until we get the RX L into the office for a more thorough examination, but after our brief taste test, we reckon there'll be no on-road penalty in opting for the seven-seat option.

Right. So this is a salutary lesson about tyre pressures. The first few days the tyres were only pumped up to 200kpa (29psi). That's an easy 100kpa (14psi) short of the required 300 (43psi).

Every time I, or my wife, went around a corner, the big Dunlop Sport Maxx SPs would squeal and squirm and it was most unsatisfactory.

So check your tyres, because the extra 100kpa makes all the difference. Also, the number of service stations it took to find a working pump was unacceptable. Pull your socks up, Sydney.

Anyway.

Correct tyre pressures enacted, the big Lexus turned into a comfortable, competent cruiser. Its motorway performance is super-impressive, purring along the M4 and it's ridiculously poor surface like it was born to it. Which it sort of was.

The hybrid drivetrain allied to the CVT is mostly whisper quiet. It's not the most responsive combination, the initial step-off of the electric motor's torque soon giving way to the rubber band effect of the transmission.

It doesn't feel as swift as the claimed 7.7 seconds and it would be nice if the drive select dial made a genuine difference to the throttle and transmission's response.

In the city, it's a proper wafter, moving about the broken down city streets of Sydney without fuss and a plush ride that's a bit of a surprise given the huge wheels and substantial weight of RX.

It's all very easy and pleasant but the wild looks do not match the experience. Which is not a criticism, just an observation.

The RX ships with eight airbags (including knee airbags for both front seats), ABS, stability and traction controls, blind spot sensor, reversing camera, forward collision warning, forward AEB and reverse cross traffic alert.

There are three top tether restraints and two ISOFIX points. 

The RX scored a maximum five ANCAP stars in January 2016.

Expect a four-year/100,000km warranty (that's 12 months longer than both Germans), and the RX L will require a trip to the service centre every 12 months or 15,000kms. Your first service is free, and total maintenance costs for the first 60,000km will run you $2031.31.

Lexus offers a fence-sitting four year/100,000km warranty with roadside assist thrown into the bargain for the same period. 

Service intervals arrive at 12 month/15,000km and there is, sadly, no capped-price servicing.

Lexus will, however, promise you a car for the day or come and get your car from you and drop it back when the service is done. And it will be washed and vacuumed. The website makes a big deal about that.