BMW M8 four-door concept teased before Geneva debut

• BMW will reveal a concept version of its M8 performance car with a four-door Gran Coupé body at the Geneva motor show. The concept, partially shown in a new shadowy picture, will preview the look and styling of the M division's 608hp range-topper in its most practical guise. Along with those new back doors, it will have a longer roofline to offer increased rear head room.

• The concept for the BMW M8 Gran Coupé – as it is expected to be called – foreshadows a production version, which is due next year. The four-door version of the M8 will sit alongside the coupé and convertible models at the top of the new 8-series range, which will appear on public roads in November.

• Although it has yet to be officially revealed, we know the production M8 models will use BMW's twin-turbocharged 4.4-litre V8 engine because the racing M8 that competed in this year's Daytona 24 Hours was equipped with this powerplant. Without motorsport restrictors to worry about, the finished road car is expected to produce 608hp. This places it above the latest 600hp M5 and giving it more firepower than the Mercedes-AMG S63 Coupé, which has 585hp.

• M division president Frank van Meel revealed that development of the M8 has started at the same time as the regular 8-series and that their programmes ran in parallel. He said that the M8 builds "on the genes of the 8-series and augments its DNA with an added track ability and generous extra portions of dynamic sharpness, precision and agility."

• "It all flows into a driving experience that bears the familiar BMW M hallmarks and satisfies our customers’ most exacting requirements,” said van Meel. He also said that BMW's engineers set out "to ensure that the standard car wasn’t too sporty for its customers", because the M division "wanted the M8 to feel like a proper step up".

• "Also, because not all 8-series customers want an M car," he added.

• “We certainly want to make a statement with this car," he said. "It will sit at the very top of our model range and, for now, we have no confirmed plans for any series production model above it, so we understand it must have a specification suiting its position in our hierarchy.”