Passenger & boot space
How it copes with people and clutter
Whereas the Porsche 911 Cabriolet provides a pair of small, but useful, rear seats, the GT Roadster is a strict two-seater like the McLaren 570S Spider and Audi R8 Spyder. However, a pair of six-footers will have plenty of head and leg room, although, due to its relative lack of in-car storage, there's not much room for your odds and sods.
And there's not a lot more room in the boot. Its 165-litre capacity is close to half that provided by the GT Coupe. That's enough for a couple of weekend bags, but not a lot else. That's another good thing about the 911's rear seats; they can double up as extra luggage space when required. Meanwhile, the BMW M8 Convertible simply offers a bigger boot, full stop.