Purists, as ever, will immediately write off the new BMW M8 Convertible as the model in the new three-car M8 range that is for those that really don't intend to use an M car as it was designed. And sure, the open-topped version is heavier and less structurally stiff, but it's still a 625hp car that the engineers at BMW M had to put their name to...
In the Metal:
The BMW M8 Convertible gets almost all the same visual upgrades as the M8 Coupe, including the wider arches, black grille, unique mirrors, big wheels, rear spoiler and quad exhaust setup. Obviously, it does without the Coupe's carbon fibre roof. Instead, the folding, multi-layer fabric top from the regular 8 Series Convertible is employed. It opens or closes in 15 seconds using the button in the centre console at speeds of up to 50km/h or by using the standard BMW Display Key when outside the car. It's a very slick operation either way, and particularly quiet. Shame that you have the remember to manually move the luggage partition in the boot for it to work, though.
Given the speeds the M8 Convertible is capable of, it's likely that you'll be deploying the windbreaker that sits over the (useless) rear seats any time you drop the roof.
Even though the M8 Convertible weighs a not-inconsiderable 125kg more than the equivalent M8 Coupe, it's remarkable that the 0-100km/h time is only 0.3 seconds longer. And having spent several hours at the wheel of the M8 Convertible on deserted and challenging roads at the launch venue in Portugal, I'd suggest that no normal person will notice the performance or handling differences between the body styles, as the Convertible's limits are way higher than most people will ever come close to in any case.
Dropping the roof does, however, allow you to hear the raucous exhaust in full flow, without the barrier of a hard top in the way, and it also serves to make the car feel especially fast when you drive with all the windows down and the air whipping your hair around.
It's not the done thing in our profession to suggest that the open-topped version of a car like the M8 is just as good as the coupe, but in this case it's certainly a close enough thing for it not to matter.
What you get for your Money:
To move from M8 Coupe to Convertible, you need to spend well over €10,000 extra, which is steep, especially given the reduction in practicality, but then again, we don't expect buyers to be rationally choosing between the two of these. Some will want the Convertible, while others wouldn't countenance such an idea. Each to their own. Those without the means to afford an M8 of any description can't hope to understand the logic.
By any measure, the BMW M8 Convertible is a ridiculously fast and accomplished car. It may be marginally slower and less capable than the M8 Coupe, but not by so much that it does its M badge a disservice. If you like your powerful M cars without a roof, then this is clearly the greatest expression of that on sale today.