BMW M4 Competition xDrive Convertible review – a cut-price Porsche 911 Carrera 4 Cabriolet?

There are a few key points to differentiate the new BMW M4 xDrive Convertible from its predecessor. Number one: it’s only available as a Competition xDrive four-wheel-drive model in the UK. Number two: the metal folding roof that has been playing havoc with the centre of gravity since the E93’s V8 screamed its way to our hearts in 2008 is replaced with a more traditional fabric affair. And number three? Whisper it… it’s not our favourite convertible 4-series.

The bare bones of the M4 xDrive Convertible (can we just call it the M4 cab?) are unchanged from those of the coupe. So there is a 503bhp, 479lb ft, 3-litre straight-six twin-turbo driving through an eight-speed torque-converter gearbox to all four corners of the chassis. It also has the same level of configurability through its driver modes: steering, throttle, gearbox, damping, braking and exhaust, and can be equipped with the same funky carbonfibre-backed seats complete with a sauce tray for your favourite fast food drive-through. And yes, that nose stays.

> 2022 BMW M3 Touring shown partially undisguised

Yes, it’s a hefty beast at 1900kg and a bit, making it 145kg more than the already portly xDrive Coupe and an obscene figure BMW should be frankly ashamed of. Today’s cars are safer than ever, but there has to be more intelligent engineering solutions than simply adding more of everything to protect the occupants. Never mind the poor sod you might hit.

Anyway, like its fixed-roof family members, the M4 cab manages to hide its weight astonishingly well without feeling aloof or you feeling totally disconnected from what’s going on. The damping doesn’t have the bandwidth on poor surfaces to match the coupe’s, and when the undulations start to roll in you can feel that mass straining at the leash to make a break for freedom. It never feels unwieldy, but were you in hot pursuit of an M4 Coupe its quad exhausts would be stretching ahead to the horizon as you measured the cab's pace to match the available control.

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As we’ve experienced with other M3/4s, the xDrive system doesn’t rob any of the sense of connection the rear-drive models deliver. But there is more damping in the steering to isolate you from the worst mid-corner intrusions, which makes for a corner entry that’s not as clean as you’d expect and you find yourself applying a small amount of lock to get the front end primed before fully committing.

Push up to its limits and the extra weight removes some of the sweetness of the hard-top cars, the neat balance not quite so noticeable and willing to be leant against, and when pushed the M4 cab feels to be cornering on its nose rather than around its midpoint.

With the roof down you won’t notice any distracting shake, but when you start to exploit the M4’s performance the loss of the rigidity a fixed roof offers manifests itself through a steering wheel that becomes very busy between your fingers very quickly and your backside reacts to every shimmy beneath you. Anything above 70 per cent of its performance capability and the M4 cab begins to struggle.

Which is where the conundrum comes in, because below it in the range sits the M440i xDrive Convertible that will save you over £23,000, yet won’t leave you feeling short-changed. If anything, you’ll probably feel you’ve come away up on the deal. Because at the speeds that the M4 cab excels, so too does the M440i. Arguably, the M440i’s more composed approach suits open-top motoring far better, with a less frantic set-up and more refined on-road manners allowing you to enjoy the benefits to be had when cruising roof down and testing the factor 50.

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Against the clock the pure M-car has the M Performance model licked, but roof-down motoring is so much more than performance figure bragging rights. Although the M4 cab’s 3.7-sec 0-62mph time will impress many.

Yet here’s the paradox. The M4 xDrive Convertible is objectively the best M3/4 of its type that has been produced, performing on such a higher level than any of its predecessors that it’s almost beyond compare. But subjectively it’s not the best six-cylinder, four-wheel-drive 4-series convertible BMW produces.

Price and rivals

A tricky one, this, because while £83,335 is a chunk of money few would consider disposable, it does make the BMW M4 Competition xDrive Convertible look ‘affordable’ against its rivals, of which there is one: the Porsche 911 Carrera 4 Cabriolet, which offers four seats (just), four-wheel drive, a turbocharged six-cylinder engine and one of the most desirable names in motoring. But at a price: £102,710. Ouch.