The official car of pro tennis clubs around the world, the droptop 4 Series isn't due in dealers until 2020 or 2021 so one would think there remains some leeway about the top. However, teams of designers are working on the new car right now, so it's entirely possible that a design course is fixed. From the time that the model made the switch, fabric roofs have got so good that there is barely, if any, penalty for using them.
It's supposed the change is being made to save weight and free up space. The next 4 Series range is aiming for a lot more sportiness, so on top of its CLAR (cluster architecture) body, it's expected to get active steering, adjustable dampers and anti-roll bars, bigger brakes, and brake-based torque vectoring. Detail improvements like reduced-friction wheel bearings, and faster torque transfer for its all-wheel-drive system are on the long list of upgrades. So too are aluminum and carbon fiber wheels, which will likely be developments based on the carbon wheels BMW showed off last year. Driver assistance options will be legion, with remote-controlled parking, semi-autonomous driving up to 40 mph, and hands-free overtaking perhaps among them.