We square off two slightly different but altogether brilliant coupe offerings to see which is best.

Can BMW make the M4 Convertible to be as fun as its brother, the M4 Coupe? To find out, BMWBLOG headed over to Munich to sample, over a series of twistier and some high-speed cruising, the new 2015 M4 Convertible.

The interior design of the new 2015 BMW M4 Convertible. The M division sees the M4 Convertible as a car requested by a small, yet passionate and wealthy M3/M4 owners. Built atop the 4 Series Convertible and the M4 Coupe, the business case for a cabriolet version is simple: high profit for relatively small changes.

While the BMW 4 Series Convertible has a hard time hiding the additional weight over the coupe, the M4 Convertible does a better job at it. Despite the 250 kg increase in weight, the M4 Convertible delivers the same handling on regular roads. We have not had a chance to sample the sporty convertible on the track, but most likely an experienced driver would notice the extra bloat.

An exhilarating blow-dry, or a heavy, pointless waste of an M car?

Time for the convertible already?

Yup, the M3 saloon and M4 Coupe are barely off the starting blocks and here comes the M4 Convertible. As sure as night follows day, the M4 Gran Coupe can't be far away. As for an M3 Gran Turismo, we'd say less likely. Much less.

Okay, enough of the usual BMW model-proliferation gags. What's the Convertible actually like?

Well, in most departments other than the obvious capability to give you a 155mph blow-dry, it's like an M4. Or and M3.

Recap please.

It's driven by a drastically capable straight-six engine with two turbos and anti-lag. An engine that fires the car forward on a perfectly controllable hurricane at pretty well any point on the rev dial. But it's an engine that although loud, doesn't have the bewitching sound or - not quite - the chef's-knife throttle response of its predecessors.

Of course in the convertible, you can take the roof down and get a bigger ear-canal load of its four tailpipes, which adds to the atmosphere. Or you can raise the well-insulated rigid roof, switch the powertrain button to a more civilised mode which closes the exhaust flaps, and use the M4 as a surprisingly civil yet rapid tourer.

But isn't it the handling that undermines chop-tops?

Usually it is. But the M4 Convertible has - just as the hard-top M4 and M3 have - a LOT of extra bracing in the engine bay and subframes to ensure that the wheels are always pointing in precisely controlled directions, untroubled by any bending. BMW M engineers say it's bending that compromises the feel and precision of a car. Torsional (twisting) flex, which most convertibles suffer from, is uncomfortable and a bit disheartening, but it doesn't actually spoil the handling.

So it proves: the M4 Convertible does twist and shimmy a bit when you drop the roof, betrayed by the steering wheel shaking in your hands, but the handling precision doesn't noticeably change.

Surely an M car has to be brilliant at corners?

Well, it's vastly grippy, and possessed of a quick-witted and confident front end. But it's a bit snappy at the back. We found the same in an M4 Coupe on our Speed Week travels recently. If you have the space to do big oversteer, it's good at it. But the zone where confident grip gives way to traction loss is a bit jittery and unpredictable. It gives the traction control quite a busy time of it.

I assume there's a weight issue.

Correct. It's an extra 250kg. Partly that's because the coupe has a carbonfibre roof and bootlid, and here they're steel. Then there's the extra body stiffening for the open car, shared with the regular 4-series Convertible. Then there's the multi-part origami roof itself, and all the fairground-ride of arms and hinges and motors needed to drive it.

Does the extra weight make much difference?

Naturally it marginally deprives you of acceleration, and costs fuel consumption, but you probably wouldn't notice except if you'd stepped right out of the coupe. The weight bias is also some way rearward, so it doesn't have the same balance on a racetrack. I didn't put that to the test, and the car's chief engineer said he doesn't expect anyone will. Owners of M3s and M4 coupes might go on the odd track day, but not convertible buyers. So he said the M4 Convertible has been set up for a slightly softer road ride.

In that respect it's surprisingly supple for a car of its cornering ability, though you can't rely on the adaptive dampers to do enough adapting. If you want comfort you need to switch to 'comfort', but that mode allows too much vertical bounce when you're clipping along, so then you have to switch to 'sport'.

So all-in, does it add to the M4 experience or compromise it?

Both. If you think an M4 should be a hardcore warrior, you won't like the Convertible's extra weight and compromised performance.

On the other hand, you might think - and we do - that the new-generation turbo M car is a different proposition, a faster but less vivid device. In which case maybe Converting it, and adding an extra string to its bow, isn't a bad idea.

From Nürburgring to Paris with the new BMW M4 Coupé.

Wheel Specs:
ADV005 Track Spec CS
Exposed Titanium Closed End Hardware
Brushed Alum. w/ Polished Alum. Windows.
21x9.5 | 21x11.5

BMWBLOG went to Germany to test drive the all-new BMW M4 Convertible. On the beautiful and fast Autobahn, we took the BMW M4 Convertible from 0 to 270 km/h.

we took the BMW M4 Convertible from 0 to 270 km/h.

Pro driver Randy Pobst hot laps the 2015 BMW M4 around Mazda Raceway Laguna Seca for Motor Trend's 2014 Best Driver's Car.

We see if BMW has maintained the magic in their latest M cars.

BMW M GmbH launches the BMW M4 DTM Champion Edition to celebrate Marco Wittmann's title win.
19.10.2014

Keen to celebrate this success in fitting style, BMW M GmbH is unveiling the BMW M4 DTM Champion Edition (0 – 100 km/h / 62 mph in 4.1 seconds, fuel consumption combined: 8.8 l/100 km [32.1 mpg imp]; CO2 emissions combined: 204 g/km)*. The Champion Edition will be built in a limited run of 23 units, reflecting Wittmann's car number. And – in a further tribute to the DTM winner – it will be offered exclusively in Alpine White. The other signature features of the special-edition model, which will be refined exclusively at the BMW Individual Manufactory in Garching (near Munich), will likewise display close links with the victorious BMW M4 DTM. The matt-black bonnet and boot lid with eye-catching stripe design make an excellent visual complement to the standard CFRP roof, as does the black character line along the car's flanks. Added to the mix are an M kidney grille with orange surround, an M logo rearwards of the front wheel arches, the number 23 on the doors and the flag along with "WIT" and "DTM Champion 2014" lettering on the rear side windows.


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BMW M GmbH launches BMW M4 DTM Champion Edition – Marco Wittmann commits long-term future to BMW and receives Formula One test.

Hockenheim (DE), 19th October 2014. DTM champion Marco Wittmann's (DE) superlative season drew to an end with yet more highlights in Hockenheim (DE). BMW Motorsport Director Jens Marquardt announced at the season finale that Wittmann will remain part of the BMW family for next season and beyond. And there were another couple of surprises in store for Wittmann in the evening after the race: BMW M GmbH launched the BMW M4 DTM Champion Edition in his honour. BMW Motorsport is also giving Wittmann the opportunity to achieve a childhood dream and complete a Formula One test for the Scuderia Toro Rosso team.

"Marco Wittmann has an extraordinary season behind him, in which he has given BMW Motorsport an awful lot of pleasure," said Marquardt. "It is now our turn to reward him for his efforts. The contract renewal for the coming season is a logical step for us, as he has consistently impressed us in the three years he has been working with us within the DTM – both on and off the track. For this reason, BMW M GmbH has come up with something very special. I am delighted that we can also make his childhood dream come true with the Formula One test. Thanks to the relationship we enjoy with our premium partner Red Bull, it was possible for us to organise a test drive in the Toro Rosso. We are excited to see how he fares in this car – and are then looking forward to more top-class performances from Marco in the BMW M4 DTM."

Dr. Friedrich Nitschke, Chairman of the Board of Management of BMW M GmbH, said: "The production version of the BMW M4 Coupé is the new centrepiece in our range. We could obviously not have hoped for anything better than for Marco Wittmann to win the BMW M4 DTM's very first race and to end the season as the champion in the drivers' and team standings. You cannot get more emphatic proof of the performance of our cars. Therefore, it is a pleasure for us to recognise Marco Wittmann's performances by launching a BMW M4 DTM Champion Edition in the colours of his Ice-Watch BMW M4 DTM. The Champion Edition will be built in a limited run of 23 units, reflecting Wittmann's car number – a very special memento of a very special season."

"I am overwhelmed," said Wittmann, given the wealth of surprises awaiting him after the season finale. "The entire season has been incredible. After all, coming into the opening race of the season here in Hockenheim, I never believed I would be standing here in the same place as the DTM champion. And then to have my contract as a BMW works driver renewed and receive a Formula One test – that is a dream come true for me. I cannot find the words to express how proud and happy I am to be part of the BMW family. The BMW M4 DTM Champion Edition in my colours is the icing on the cake at the end of this outstanding year. The car looks fantastic. I can hardly wait to take it out for a drive. And the test in the Scuderia Toro Rosso F1 car will definitely be an amazing experience."

In a tribute to the Ice-Watch BMW M4 DTM, the Champion Edition will be offered exclusively in Alpine White. The other signature features of the special-edition model, which will be refined exclusively at the BMW Individual Manufactory in Garching (near Munich, Germany), will likewise display close links with the victorious BMW M4 DTM. The matt-black bonnet and boot lid with the eye-catching stripe design make an excellent visual complement to the standard CFRP roof, as does the black character line along the car's flanks.

Added to the mix are an M kidney grille with orange surround, an M logo rearwards of the front wheel arches, the number 23 on the doors and the flag along with "WIT" and "DTM Champion 2014" lettering on the rear side windows. The BMW M4 DTM Champion Edition is also fitted with 19-inch light-alloy wheels, a black front splitter, a black side skirt blade, carbon front flaps, carbon mirror caps, a rear spoiler and a carbon diffuser insert from the M Performance Parts range.

The Champion Edition underlines its exclusivity once again when you step inside. The door sill plates bear Marco Wittmann's autograph, while carbon interior trim strips – likewise signed by the 24-year-old from Fürth, Germany – feature "DTM Champion 2014" lettering and the car's serial number.