KTM X-Bow vs BMW M4

What's the difference?

Okay, so rain is not your friend. Neither is brutal sunshine, strong winds or any speed bump anywhere. There are probably a handful of times you'll want to drive it, and when you do you will definitely get hit in the face with rocks and bugs, and spend most of your time wondering just how the hell this thing is legal.

And yet, we are hopelessly, head-over-heels in love with it. It's an absolute weapon on a track, a joy on anything even resembling a twisting road and it is one of the few genuinely unique cars on the road today. And the fact it exists at all is a cause for absolute celebration.

We cannot think of a faster or more invigorating four-seater luxury convertible for the money than the new M4 Competition.

Finally, after years of devastatingly fast droptops with remote steering and an unforgiving ride, the G83 generation discovers refinement and sophistication to go with its supersonic speed.

There’s terrific talent on tap here that no rival can even come close to right now. BMW is on a roll and this is the first M4 convertible that can sit proudly alongside the best of its classic M3 ancestors.

The X-Bow R is built for purpose in the most wonderful of ways. From the visible suspension components to the rocket-style exhausts, to the stripped-bare interior, it's fairly obvious that form came a distant second to function in the X-Bow's design process.

And, for us at least, that's a tremendous thing. It looks raw and visceral, and a bit like Harvey Dent post-fire - you can see all the normally hidden components doing their thing. It's mesmerising.

Hallelujah! The unloved folding hardtop is history and fabric is back in fashion in a BMW 3/4 Series-based convertible for the first time since the demise of the E46 convertible in 2006.

It improves the proportions and aesthetics out of sight while remaining superbly insulated. It’s also 40 per cent lighter to boot while liberating 80 litres of extra luggage space.

The roof requires just 18 seconds to drop away or erect again, and can be done so at speeds of up to 50km/h. And it looks great, with a taut fit that suits the BMW’s lithe lines to a tee. With all four windows dropped, it also does a fab impression of an American-style pillarless hardtop.

Roof up or down, the M4’s muscular styling has a tense sparseness to it that means business, reinforced by that oversized, M-specific kidney grille treatment that, admittedly, isn’t as divisive in real life. The smiley LED light wave out back also brings a friendlier tone, harmonising handsomely with the rest of the car.

This is probably the best-looking BMW convertible since the beautiful E46 era.

Short answer? It's not. People are unlikely to test drive an X-Bow R and start looking for cupholders and storage space, but if they did, it wouldn't take long.

Aside from the twin seats, a four-point racing harness, a high-mounted gearshift, a pull-lever handbrake, and detachable steering wheel, the cabin is as bare as Old Mother Hubbard's cupboard.

Luggage space is limited to what you can carry in your pockets (though wearing cargo pants will help) and even getting in and out of the thing takes some fleet-footed antics. With no doors you need to literally jump in. And the side sills are only rated to 120kg, so heavier types will need to avoid stepping on them at all, and instead attempt a kind of running leap into the cockpit.

The M4 Convertible is not a paragon of space efficiency, given its footprint.

At nearly 4.8 metres long and 1.9m wide, the M4 Convertible casts a sizeable shadow on the road, which only really pays dividends for front-seat occupants inside.

Ours was fitted with a very handsome pair of $7500, two-tone M Carbon bucket seats up front, a sort of futuristic tombstone design with a fixed headrest that looks like they were created by and for Stormtroopers; they do provide all the electronic adjustability one would need in terms of fore/aft, up/down and lumbar support movement.

But, unless you really need their g-force-bracing support and love their outrageous appearance, they are monumentally obstructive to effortless entry/egress and overall hip comfort if you don’t possess a gymnast’s physique. In fact, at times, they can feel downright torturous, especially in the gusset area due to the pointless (ironically) hard central bulge bit. The standard front seat set-up is perfectly fine, offering all the comfort and support expected in a luxury convertible, with the added bonus of headrest adjustability.

As with all G20/G80 generation 3/4 Series, the M4’s interior is a welcome return to form for BMW, from the excellent driving position and superb build quality, to thoughtful switchgear placement, brilliant ventilation and ample storage. And iDrive is probably the best and most intuitive multimedia system out there, too, needing no special skill or distraction once mastered.

A quick note about the instrumentation. The 4 Series design digital readouts are prettier than the standard 3 Series' ugly standard screen that looks ex-Honda Civic. This one offers alternative views and is easy to read at a glance. But it still makes us pine for good old analogue dials. Remember when BMWs were the world leaders in dial design?

Some familiarisation is also required to figure out the M part of the M4, including the various driving and performance modes; they’re divided into Road, Sport and Track settings. Yet, thankfully, they’re all far simpler to get your head round than before, which required too much fiddly concentration, since – once quickly learnt – everything is possible with eyes-on-the-road promptness. A new M Mode button offers pre-determined shortcuts to whichever drive combinations are desired.

The roof is well insulated, meaning that previous-gen folding hardtop-owning prospective buyers shouldn’t be too sad about the fabric above their heads. On the go, front occupants can enjoy a variety of configurations, starting with snug coupe-style cosiness and security, moving to cool pillarless hardtop-style windows-only down cruising, to the full top-down convertible glory. The latter also brings minimal buffeting at speed unless you’re stuck out in the back. Roof-up vision isn't brilliant, though.

Strangely, with the M Carbon bucket seat options ticked, it’s actually easier for some people to get into the back than the front. Pulling a strap sees the front bucket seats (slowly) whir as far forward as possible to allow sufficient room for people to clamber onto the rear seats.

Once sat, it’s clear that longer-legged people will struggle. Knee room is OK (especially if the front occupants are feeling sympathetic by moving their seats forward), there’s surprisingly adequate head room for your 178cm tester when slightly slouched, big feet can be tucked beneath the front seats and scalps never have to touch the rear glass thankfully.

And at least BMW has tried to make life back there comfier for smaller people, due to rear-facing air vents with climate and directional control, two USB-C ports, a pair of cupholders, a centre armrest and some handy storage. The materials are of a high quality construction, too.

However, the fixed back rest is far too upright, the knees-up posture quickly gets tiresome, the cushion is firm and you’re sat on a slight angle pointing outwards. Claustrophobics won't be too happy either. Annoyingly there aren’t side window buttons either, meaning only the driver can lower or raise them. The two-seater back seat is best saved for short trips or kids.

Happily, once the roof is dropped, the hemmed-in feel vanishes, there’s not too much wind intrusion or buffeting with the side windows up and there’s a sense of shared freedom that only a four-seater convertible can bring. Going the full drop-top experience will ruffle more than hairdos at freeway speeds, though. An optional wind deflector can fix that issue for front-seat occupants, but it goes over the back seats, turning the M4 into a two-seater ragtop.

Further back, the 300-litre boot isn’t accessible from the cabin, meaning you can’t put much inside at all. BMW fits a hinged flap that needs to be down for the roof to work since it cordons off the roof storage part of the boot when folded in; when lifted, there’s a useful amount of space for luggage, and it’s a handy rectangular shape instead of an L-shaped slot, but obviously at the cost of convertible driving. You can’t have both.

Note that, compared to the previous folding-hardtop M4, this boot is some 80L larger. 

There’s only one M4 Convertible available, in Competition M xDrive guise, and it’s not lacking for much.

We’re looking at a 375kW/650Nm 3.0-litre twin-turbo in-line petrol six-powered four-seater AWD ragtop capable of 0-100km/ in 3.7 seconds, on the way to either a 250km/h or optional 280km/h top speed, if your wallet allows. All from $176,900 before on-road costs. BMW’s serious here.

Standard features include an active M differential, adaptive suspension with auto levelling, an M Compound Brake package and selectable driving modes, underlining the M4's driver focus.

You'll also find leather upholstery, head-up display, adaptive cruise control with full stop/go functionality, automatic parking assist, a surround-view camera, a lap timer and “drift analyser”, paddle shifters, wireless smartphone integration including Apple CarPlay/Android Auto connectivity, emergency services access, three-zone climate control, electric front seats with memory, front seat heaters, ‘air collar’ neck warmer, keyless entry/start with BMW Digital Key, key fob control for windows, roof and boot opening, split-fold rear backrest, M carbon fibre trim, leather steering wheel, a 12.3-inch instrument display, a 10.2-inch control display, 16-speaker Harman/Kardon surround-sound audio system, digital radio, MP3 player, cloud-based satellite navigation, trip computer, wireless charging, ‘Hey, BMW’ assistant, outside connected services assistance, ambient lighting, BMW LED Laserlight auto high beams with active cornering and light sensitivity, rain-sensing wipers, electric heated/folding exterior mirrors, tyre pressure monitors, 19-inch front/20-inch rear wheels/tyres and a tyre repair kit.

Taking care of safety are six airbags, forward collision warning, Autonomous Emergency Braking (AEB) front and rear, with front/rear cross traffic alert, lane departure warning with passive steer assist, lane keep with active assist, blind spot monitor, 360-degree view cameras, parking assist, parking sensors, anti-lock brakes with electronic brake-force distribution and brake assist, stability control, traction control and corner braking, among other features. More details in the safety section below.

Our BMW also included three options that detracted from the M4’s comfort and/or taste: $5000 Frozen Portimao Blue paintwork, $7500 M carbon bucket seats and $8500 M Carbon exterior package, upping the total unnecessarily to $197,900 before ORC.

Rivals in the 2+2-seater ragtop arena are few and far between. With no Audi RS5 Cabriolet in existence, Audi only has the S5 Cabriolet from $126,200, but that’s up against BMW’s M440i Convertible from $135,900. There’s more parity with the ageing Mercedes-AMG C 63S Cabrio from $202,177 and softer Lexus LC 500 Convertible from $213,877, while the cheapest Porsche 911 Carrera Cabrio will set you back a cool $262,900.

Seen in that light, it’s fair to say the standard M4 Competition xDrive is in a league of its own – particularly when you factor in the BMW’s ability to more-or-less equal and even exceed the others at their own game. And that’s something the previous version could not achieve.

So, that’s a surprising yes for value.

The X-Bow R's power comes from an Audi-sourced, turbocharged 2.0-litre engine, paired with a VW Group six-speed manual transmission (and one of the stubbiest gearsticks in existence). That mid-mounted marvel produces 220kW at 6300rpm and 400Nm at 3300rpm, and ships it off to the rear tyres with the assistance of a Drexler mechanical limited-slip differential.

Thanks to its lithe and lightweight body, that's enough to propel the X-Bow R from 0-100km/h in a blistering 3.9 seconds, and on to a top speed of 230km/h.

Here is a summary of Australian-market outputs and prices for the M3 and M4 convertible autos, with the prices in brackets being approximate inflation-adjusted figures for today.

1999 E36: 236kW/350Nm 3.2L in-line six-cylinder engine (I6), $152,000 ($266,000 in 2022); 2003 E46: 252kW/365Nm 3.2L I6, $158,000 ($240,000); 2008 E93: 309kW/400Nm 4.0L V8, $183,442 ($240,000); 2014 F83: 317kW/550Nm 3.0L twin-turbo I6, $178,430 ($202,000).  

In 2022, the G83 M4 Competition lives up to its name in more ways than one, with a 2993cc 3.0-litre double overhead cam direct-injection twin-turbo I6 known as the S58 series, which is itself derived from BMW’s B58 modular family of engines. Its 375kW is delivered at a lofty 6250rpm, while there’s a 650Nm plateau of torque between 2750rpm and 5500rpm.

A kerb weight of 1920kg means the M4’s power to weight ratio is an impressive 195.3kW/tonne, helping its published 0-100km/h time of 3.7s. For a few grand extra, the company will up the top speed by 30km/h, to 280km/h.

BMW says the engine includes cooling and oil supply systems designed for extreme lateral forces at high speeds, while the exhaust uses electrically controlled flaps for a more raucous noise.

Power is channelled to all four wheels continuously via an eight-speed M Steptronic transmission with a trio of shift programs. The AWD system features an active differential to better transmit torque to all four wheels, while drivers can choose one of three, progressively more rear-wheel drive (RWD) biased modes: 4WD, 4WD Sport and 2WD – the latter being a pure RWD set-up.

Other related changes the M4 boasts over regular 4 Series models include special stability and traction control tuning, a double-joint spring strut front axle with unique axle geometry and variable-ratio steering, a five-link rear axle featuring its own kinematics and elastokinematics, M-specific adaptive dampers, a configurable braking set-up according to feel and response, and forged M light-alloy 19-inch alloys up front and 20-inch items out back.

Choosing the AWD-only convertible over the equivalent AWD coupe adds 145kg (and 195kg compared to the RWD coupe), though this is partly offset in two ways over the preceding, folding-hardtop M4 Convertible: firstly, using the soft top drops weight by 80kg; and secondly, while the AWD system does add 50kg, it’s at a lower centre of gravity, thus naturally improving vehicle dynamics.

Which are electrifying, by the way.

KTM lists the X-Bow R's claimed/combined fuel figure at 8.3 litres per hundred kilometres (though we were managing mid-12s after an, ahem, very spirited test), with emissions pegged at 189 grams per kilometre.

The X-Bow R is also fitted with a 40-litre fuel tank, accessed via a side-mounted inlet. Instead of a fuel gauge, expect a digital reading showing how many litres you have left.

We managed 12.1 litres per 100km in a mixture of urban, freeway and rural-road driving, including plenty of performance testing. This is a two-tonne M4 convertible capable of supercar speeds, after all. In that context, the economy is more than acceptable. No doubt the stop/start engine function (at idle) helps here.

For the record, the official combined-average claim for this Euro 6-rated BMW is 10.4L/100km, for a carbon dioxide emissions average of 237 grams/km. Thanks to a fuel tank that holds 59 litres of 98 RON premium unleaded petrol, it can manage an average of almost 570km between refills.

It couldn't be more Fast and Furious if it had Vin Diesel growling under its (non-existent) bonnet. We have technically driven faster cars, but we have never driven anything that feels quite so fast as this utterly insane X-Bow R.

Climb in, strap into the four-point harness and select first via the surprisingly easy-to-manage gearbox and clutch set up, and, at slow speeds, wrestle with the dead weight of the completely unassisted steering, and it's immediately clear that this is a driving experience like nothing else currently road-legal in Australia. Even at walking pace, the X-Bow R feels poised for an assault on the future, and it attracts attention on the road like nothing else we've ever driven.

Its road-scraping ride height and diminutive dimensions make tackling traffic an intimidating prospect, with regular hatchbacks suddenly taking on truck-like proportions and actual trucks now looking like passing planets. There's a constant concern that you're sitting well below the traditional blind spot, and that you could be crushed at any moment.

Combine all that with the bad weather that cursed our final day of testing, and the X-Bow R is all sorts of watery hell. It is truly homicidal in the wet, too, with the back end breaking grip at the slightest provocation. And the turbocharged 2.0-litre offers plenty of that.

But on a sunny day, and on the right road, it's pure driving bliss. The acceleration is brutal, the grip endless and the Audi sourced gearbox an absolute treat. And it pulls in every gear, tackling 35km/h corners in third and absolutely blasting out the other side.

Cornering is scalpel sharp, and the steering - so heavy at slow speeds - is light and efficient at pace, requiring only the most minuscule of movements to bite into a bend.

It is anything but perfect in the city, and even a light sprinkling of rain will have you seeking shelter (and a refund), but on the right road, on the right day, there are few if any cars that offer the kind of razor-sharp thrills and intoxicating excitement of KTM's monstrous X-Bow R.

Marvellously.

Earlier, we said that the previous M4 (and some earlier M3 generations) never hit the dizzy heights the best like the E46 managed.

The reason why is bandwidth. Not WiFi bandwidth, but rather the newfound breadth of capability that the G83 model has acquired.

Yes, while even the slowest examples of previous M3s and M4s remained thrilling, with blisteringly potent acceleration accompanied by a soaring exhaust soundtrack, the post-E46 models seemed to become almost too obsessed with the pursuit of performance. Thunderous V8s and twin-turbo V6s are all good and well, especially when they provide explosive responses, but there’s more to sports cars than sheer bloody-minded speed.

More specifically, though the handling and roadholding were outstanding, the previous M4’s steering didn’t feel as connected or one with the driver, instead seeming a little remote and detached. Conversely, even with adaptive dampers on offer, the suspension (on Australian roads) lacked sufficient isolation from bumps and thumps, and so was never settled or calm. It was all too nervous and edgy, like a drug-addled athlete who’s indulged in too much partying.

Thankfully, the curse is broken with the latest iteration, even in the heaviest and slowest version like our M4 Convertible as tested, pushing out boundaries to thrilling effect once more.

With the newly-simplified and logically presented M performance modes only a push of a button away, the driver now no-longer has to concentrate on what setting they’re in, and instead just immerse themselves in the experience of accelerating, steering, cornering, braking and controlling this incredible sports convertible.

Tremendously strong in regular Road mode, the M4’s performance certainly lives up to the legend, stepping up into the supercar realm when Sport or Track are chosen, hunkering down as it thrusts towards the horizon with relentless speed and determination, accompanied by the gorgeous twin-turbo six’s revs as they soar towards the red line. The ultra-alert eight-speed auto’s operation is equally seamless, displaying uncanny intuition in its selection of the right ratio at exactly the right time.

These are all incremental improvements over what has come before. But what’s really changed is how rock-solid the BMW feels as it belts along at speed, magnetised to the motorway regardless of weather, its new AWD engineering keeping everything steady and planted. No more tetchiness to unnerve the driver.

Which makes the feel and fluency of the chassis even more remarkable, given that now all four wheels are driven. The very opposite of leaden or inert, the superbly weighted steering is instead light and alive in your palms, as you carve through corners with pin-point precision. Some might find it a bit too eager to change direction at first, but we reckon BMW has judged the balance just right. Its sheer agility is as life-affirming for driving enthusiasts as it is immersive. Bravo, BMW.

With so much grip and control, this is not to say that the driver can’t hang the M4’s tail out every-which-way, since the chassis set-up allows for progressive oversteer, even in Road mode, along with as much drifting as your courage allows where safe. As with the best sports cars, the M4 is as steerable from the seat of your pants as it is using the throttle.

Finally, there’s the M Adaptive chassis tune, that at long last broadens the M4’s repertoire from motorway grand tourer and rural-road blaster to city slicker and urban warrior, thanks to the suspension’s ability to better-absorb a much wider array of terrible road surfaces. Comfort now lives up to its name, with the ride – though still firm – no longer hard or crashy around town, ushering in a new level of civility that won’t fatigue or aggravate you or your occupants. We're so happy to report this progress.

One area where BMW might want to keep improving, though, is the abundance of road noise intrusion over certain coarse chip bitumen. While easily muffled by the sweet sounds of the twin-turbo six, banging audio system or dropping the roof, it now seems more obvious that the rest of the car has smartened up so much.

A small fly in an otherwise hugely satisfying ointment.

There is no specific crash-test data for the BMW G83 M4 Convertible.

However, tested in 2021, the G23 4 Series Convertible it’s based on (and tested in European-spec 320d guise) managed to score a five-star ANCAP rating, and performed strongly across each of the main disciplines – adult protection, child protection, vulnerable road-user and safety assist categories, achieving 96 per cent, 86%, 93% and 73% respectively.

Standard safety features includes six airbags (a driver’s knee airbag, dual frontal, side chest and head-protecting airbags for the first row and side chest protecting airbags for the second row), forward collision warning, Autonomous Emergency Braking (AEB) front and rear, with front/rear cross traffic alert, lane departure warning with passive steer assist, lane keep with active assist, blind spot monitor, 360-degree view cameras, parking assist, parking sensors, anti-lock brakes with electronic brake-force distribution and brake assist, stability control, traction control, corner braking and tyre-pressure monitors, BMW LED Laserlight auto high beams with active cornering and light sensitivity and rain-sensing wipers.

The AEB technology is rated for City, Interurban and Vulnerable Road User, according to ANCAP, and works between 5km/h and 210km/h in daytime and nighttime conditions.

There are also two ISOFIX points as well as two top tethers for straps in the rear seats.

The X-Bow R is covered by a two-year, unlimited-kilometre warranty, and while service prices aren't capped, Simply Sports Cars estimates an average serve cost at about $350.

We feel here is where the company drops the ball.

Trailing all of its main luxury car rivals (except Porsche) by two years, BMW only offers a three-year/unlimited kilometre warranty, as well as three years of roadside assistance.

BMW says its vehicles’ servicing is condition-based, depending on how they’re driven and other factors, with a dash warning appearing to let the driver/owner know when it’s time. We advise servicing your M4 annually or at every 10,000km, just to be sure.

No capped-price servicing system is offered. However, as long as the first one is paid for before the first service on a new vehicle, the ‘BMW Service Inclusive Basic packages’ is available at extra cost, covering scheduled servicing for three years/40,000km or five years/80,000km.

No prices are published for M models like the M4, but a normal 4 Series costs from $1800 for the five-year/80.000km package. You can bet an M4’s will cost more.