Porsche 911 vs BMW XM

What's the difference?

The more things change, the more they stay the same. The t-hybrid might be an entirely new propulsion system for the 911, but the net result is unchanged – power, poise and performance on tap.

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

It’s pretty obvious the XM is designed to impress people with big wallets and an appetite for a techy experience that’s also not without a few green credentials. The ability to motor around as a fully-electric vehicle for up to 80km or so is a big plus and the electric-ballroom interior vibe is hard to ignore, as well.

But from our perspective, the full-fat, twin-turbo V8, while offering startling performance, is perhaps a lost opportunity to follow some of BMW’s competitors into the engine-downsizing space. Then again, when you floor the throttle and 2700kg hurtles forward like a big dog on a short chain, you can see where BMW is coming from.

Perhaps the biggest letdown is the ride quality – or lack of it. While it’s understandable BMW wanted the most dynamic version of the XM it could manage, the end result plays against the vehicle’s otherwise long suit of hyper-luxury. Doubtless, BMW would argue that to soften the chassis would have been to introduce a chink into a no-compromise product. But, perhaps, sometimes a sensible compromise is the way forward.

This facelift debuts a revolutionary exterior design that has completely reshaped the 911.

Just kidding. If it ain’t broke and all that. The front air vents and exhaust have changed, the former now an active intake system that deploys via vertical flaps, but elsewhere it’s largely evolution over revolution.

Instead, Porsche has focused most of the updates in then cabin. In here, you’ll find a new digital instrument panel, they’ve changed some of the levers and the steering wheel.

In true Porsche fashion, though, this new 911 mimics the older versions in that it's one of the more intuitive cabins you’ll ever sit in. Everything feels as though it’s exactly where it should be, and all feels entirely centred on the driver.

There’s nothing subtle about the way the XM looks. It probably pulls up just short of brutalist (or maybe not) but even those who find its slabs and angles attractive have to admit that it’s bold.

The now-trademark giant nostrils set the mood and the rest of the exterior suggests some kind of armoured transport for presidents rather than wheels for the school run. Doubtless, this will hardly be seen as a fault by those in the market for such a thing.

The real surprise here is that the XM does not share a bodyshell with any other production BMW. Sure, the V8 petrol engine and wheelbase are common to other BMW and M models, but the sheet metal is the XM’s and the XM’s alone. That in itself, is quite a statement of intent.

This probably falls under the ‘next question, please’ umbrella, given that, while the Porsche 911 is known for a lot of things, vast acres of space with loads of practicality perks just ain’t a part of its portfolio.

The new 911 measures a not-insubstantial 4533mm in length, 1852mm width and around 1294mm in height, and it rides on a 2450mm wheelbase. Luggage space is a paltry 135 litres under the bonnet, plus whatever else you can fit in your pockets.

There’s seating for four, should you not like the people you’re squeezing back there very much, but really the 911 is best enjoyed as a two-seat proposition – which is why you can also delete the backseat, should you wish.

It also weighs a minimum 1595kg, or up to 1745kg, but Porsche says the hybrid tech only adds about 50kg to the total kerb weight.

Given the vast exterior dimensions and a weighbridge ticket the wrong side of 2700kg, it may come as a surprise to learn that the XM is strictly a five-seater with not even an optional third row.

That said, the uber-SUV Lexus LX in flagship, Ultra Luxury, trim offers just four seats in deference to the VIP clientele it’s pitched at, but also comes complete with reclining rear seats and a passenger’s side footrest which the XM can’t match.

Staying in the rear seat, there’s lots of legroom and plenty of space under the front chairs for feet. A lot of that is down to the wheelbase the XM shares with the BMW X7, and even behind a tall driver, there’s lots of space. In fact, compared with a BMW X5, there’s a full 150mm of extra legroom.

The pew itself flows into the door trims for a lounge effect which looks great with the contrasting light-coloured trim, and the centre arm-rest folds down to reveal a pair of cupholders. Extra storage space can be found in fold-out pockets in the rear of each front seat which also house a small, lidded panel that opens to reveal USB ports and power sockets. Dual-zone climate controls are also part of the rear-seat experience.

The gee-whizz stuff hasn’t been ignored, either, and the prismatic roof lining is nothing if not a talking point. But would a panoramic sunroof have been of more value to many buyers? The ambient lighting is a nice touch, too.

Up front, the view is dominated by the giant, twin curved animated dashboards. They deliver information and lots of it, to the point where it can almost seem a bit overwhelming.

The head-up display helps simplify things, but there’s absolutely no doubt there’s a lot going on in this cabin. Again, this is modern luxury motoring, but it remains that the menu system will take time to learn, even if the touchscreen function gives you an option on how you control things.

Multi-adjustable front seats are part of the deal and there’s an M-spec steering wheel which is heated. And although it features plenty of buttons, isn’t as daunting perhaps as the multi-spoked equivalent in some high-end AMGs of late.

The stereo system is also worthy of a mention, being a Bowers & Wilkins unit with roof mounted speakers and no less than 1500 watts of power. Digital radio is part of the package.

Even though it doesn’t offer a seven-seat option, luggage space in the rear of the XM is hardly class-leading. Cargo volume with rear seat up is 527L and 1820L with it folded.

Much of the wheelbase is devoted to rear-seat stretching room and although the batteries for the electric motor are positioned under the rear seat, the floor of the cargo area seems quite high.

The XM is one of those 'no options' vehicles. That is, you pay the basic price, you get one with the lot. The aged leather and even the optional 23-inch wheels and tyres are no-cost options, so it’s clear where BMW is aiming the thing.

As well as the plug-in driveline, all-wheel drive and all the M driving focus, the XM features plenty of tech including massaging front seats, heated seats all around, a high-end stereo, heated and cooled cupholders, four-zone climate-control, wireless phone charging and twin, curved info screens for the driver measuring 12.3 and 14.9 inches. The novel roof lining also features 100 pin-point LEDs for effect.

The cost of such detailing is a not insubstantial $302,200. That figure does, however, undercut two of its main rivals, the Lamborghini Urus ($395,888) and the Aston Martin DBX ($356,512).

It’s also worth mentioning that the XM is not even BMW Australia’s most expensive model; in fact, it’s fourth on the ladder.

A new (or at least, massively altered) 3.6-litre petrol engine has been developed for this T-Hybrid, which combines with two electric motors to produce a total 398kW and 610Nm. It’s only available with Porsche’s very good eight-speed Porsche Doppelkupplung (PDK) automatic, largely because the brand admits it would be… well… unpleasant to drive as a manual.

Now, there is lots of magic at work here, and I don’t want to bore you, but the Porsche setup sees a lightweight 1.9kWh battery placed basically in the middle of the front axle, and a 12-volt battery now behind the front seat. Then, a tiny e-motor lives as part of the gearbox (it’s just 55mm long) and delivers up to 150Nm at low speeds to supplement the petrol engine.

It’s joined by what Porsche calls an “electric exhaust gas turbocharger”, which essentially removes the spooling time from the turbo, delivering instant power.

The aim of the game here is excitement, not efficiency, and the launch-control-aided spring to 100km/h takes just 3.0 seconds. And it somehow feels, and sounds, faster.

The latter being important, with Porsche aware that if the new powertrain didn’t sound good, "nobody would like it”.

Here’s where the XM starts to justify its price-tag. While the use of an electric motor to boost a petrol engine has allowed some manufacturers to reduce the capacity of the latter, no such restraint has been shown for the XM. Instead, it gets the full 4.4-litre, twice turbocharged V8 that we’ve come to know and love from this brand.

It’s not that this is the engine’s first date with hybrid technology, but the mild hybrids that have come before it can’t match the XM for sheer brutality when both power units are unleashed.

The petrol V8 can muster up 360kW and 650Nm which, when boosted by the electric motor, jumps to a total of 480kW (combined) and 800Nm.

While the petrol engine drives through an eight-speed torque-converter automatic, the electric motor also drives through the transmission, an arrangement that is a bit different to some hybrids which use the petrol engine for the rear axle and the electric motor to drive the front wheels.

Of course, the requirement for the XM to feature permanent all-wheel drive, regardless of what power unit is running at the time, forces this layout.

Speaking of all-wheel drive, The XM’s version of BMW’s 'xDrive' layout has been specifically tuned for this vehicle and includes torque vectoring as well as a limited-slip rear differential.

The system has the ability to vary the torque split front to rear, with the default rear-bias giving a more sporting feel on good surfaces. An active rear differential also helps give the car a rear-drive feel.

As well as modes for 'Hybrid', 'Electric' and 'eControl' modes, the XM sticks with the M tradition of offering two M buttons which can be configured to set the parameters for steering, driveline, chassis and, in the case of the hybrid XM, the degree of braking regeneration offered.

Four-wheel steering is also part of the XM’s repertoire and, interestingly, there’s no air suspension here; just conventional steel springs.

But it does feature an electrically-adjusted anti-roll bar system which aims to strike a happy medium between what the driver wants and the road conditions demand.

Porsche in Australia is yet to lock in local fuel use for the Carrera GTS T-Hybrid, but international testing has it at 10.5-10.7L/100km, C02 emissions of between 239-244g/km. 

Those aren’t exactly Toyota Prius numbers. But again, that was never Porsche’s intention. The electric power on offer here is intended to improve acceleration, not fuel use.

It’s fitted with a 63-litre fuel tank, which should deliver a driving range of around 600km per tank.

A 25.7kWh lithium-ion battery provides the power for the electric drive. It’s mounted under the rear seat and can produce a purely electric range of between 82 and 88km (based on WLPT test protocols).

Charge time from a conventional wall-box is said to be about four hours but, interestingly, the XM has no provision for DC fast-charging.

Fuel consumption (combined cycle) is an EV-typical 2.7 litres per 100km, which equates to a low 61g/km of CO2.

Once you’ve depleted the battery on a highway journey, expect the petrol V8 to consumer somewhere between eight and nine litres per 100km at cruising speed.

Using EV mode means zero-emission operation but, as with any electric car, how the power is generated to recharge it determines its real-world green-ness.

Porsche did just about the Porschiest thing to ever Porsche in launching the 911 Carrera GTS T-Hybrid, in that we piled into cars in Melbourne, drove the many, many hours (well, it feels that long, at least) to the Phillip Island race circuit, beat the hell out of the cars on track and on the drag strip for several hours, then trundled back out on the road and drove them back to Melbourne.

The subliminal messaging here is pretty clear. This new 911 might have a new powertrain, but it can still deliver the road-track-road experience without breaking a sweat — or, more importantly, without breaking any expensive bits.

So let’s do this in order, shall we? On the road, this new 911 is every bit as sweet as it has ever been. Comfortable, quiet enough when you want it to be, and — save some road noise from those big wheels – quiet enough to let you forget you're driving something with one of Peter Dutton’s nuclear reactors hidden beneath its svelte metal work.

Mind you, that T-Hybrid powertrain will happily remind you of its presence every time you press the accelerator in anger, the exhaust erupting into life and the 911 genuinely rocketing into the future, but stay gentle with your inputs and this hybrid 911 is a genuinely comfortable, genuinely liveable daily driver.

Its split personality appears when you rumble out onto a race track though, where you quickly discover the electrified, and electrifying, Porsche is properly, properly rapid, both in a straight line or around Phillip Island’s fast and flowing circuit.

It’s so rapid, in fact, that it feels most closely related to a performance EV, like the Taycan. Of course it is louder and more engaging, but that’s the best way I can think of to describe the instant power on offer here. There’s no ICE-like lags or lumps in the way that 398kW and 610Nm finds its way to the tyres and into the tarmac. Instead it’s just this constant, savage flow of power that never seems to let up.

Porsche says this new powertrain is about 50kg heavier, but you’d need to be plugged into the race track like its the Matrix to ever feel it, with the T-Hybrid feeling lithe, grippy and athletic, aided by near-perfect steering, the best automatic gearbox in existence, and exactly zero roll through the body. In fact, the only thing that really moves when cornering hard in this new 911 is the driver, and I genuinely got out after several laps with a sore neck from trying to stay vertical.

Downsides? Well, it’s faster in a straight line (it will be some 7.0m further down the road after 2.5sec when compared to the older GTS) and faster around corners (8.7sec faster around the Nurburgring than its predecessor), but there’s something delightfully analogue about the outgoing car, which also manages to feel more aggressive under heavy acceleration, too, owing to the little ebbs and flows of power, and after driving both back-to-back, I still can’t decide which one I like more.

While any M car is supposed to be rapid and dynamic, it’s also true that the over-arching perception of big SUVs is that they’re comfortable and plush. None of which explains the ride in the XM.

Regardless of how you fiddle with the settings, the ride is always brittle. Those big tyres with their minimal sidewall somehow manage to find every crack and join in the road, and it’s these sharp-edged imperfections that thump through to the cabin the most vocally.

It’s enough to make you wonder who this car is going to appeal to. Will it take to race tracks? Almost certainly not. So the whole point of these suspension settings might be a bit lost on some people.

Performance, meanwhile, is insanely rapid for something that could pass as a bulk carrier. The biggest giveaway to the mass is the transmission’s earnest attempts to keep everything moving by feeling a bit hyperactive on downshifts.

Using the ratios is always going to be the strategy, but with all that torque, maybe it’d be nice sometimes for the trans to hang on to a taller gear and let the boost blow it towards the next corner.

The sound track? Polarising. Even if it doesn’t convince you that Hans Zimmer (who developed the various electronically-synthesised noises the XM makes) should stick to winning Oscars, the augmented sounds are background noise rather than the main event here.

Even the petrol V8’s naturally stirring backing vocals have been electronically tweaked with debatable results.

That said, it’s nice to have something to listen to that isn’t the insistent tyre roar which becomes even louder on coarse-chip surfaces.

Steering effort is light but there’s not a lot of feedback in terms of actual feel. In fact, it’s borderline detached and only the sheer speed of the rack confers any athleticism.

Also, the rear steering seems to come in a few milli-seconds after the front has started to turn. And for all that all-wheel-steering agility, this is never a car that shrinks around you.

As well as the usual passive safety features, the XM also hides the latest active safety gear. In fact, BMW reckons the XM has more driver assistance than any other M car before it.

Those elements start with the 'Driver Assistant Professional' which bundles active cruise-control with stop-go ability, steering and lane-keeping control, automatic speed limit assist and active navigation.

Parking assistance is also featured which incorporates a reversing assistance function, front, rear and panoramic camera views with a 3D view built in.

BMW’s 'ConnectedDrive' includes an emergency call function in the event of a crash or other emergency.

No ANCAP assessment so far.

The 911 Carrera GTS is covered by a pretty underwhelming three-year, unlimited-kilometre warranty, with servicing required every 12 months or 15,000kms. We don’t have the hybrid service pricing yet, but as guide, the last 911 split the services into minor and major, and charged either $785 or $1285 for each.

Like a lot of manufacturers, BMW knows consumers can be leery of EV tech when it comes to the cost of battery replacement. So, as well as the five-year/unlimited-kilometre warranty on the whole vehicle, there’s also eight years or 160,000km of cover for the high-voltage battery.

Servicing intervals are based on how the car has been used and it will inform the owner when a service is required.

A servicing package is included in the purchase price and BMW even throws in three years of roadside assistance.