Some four decades since the M1 became one of the best-known sports cars of the 1970s, BMW’s single-lettered subsidiary M is now working on its first original car. But this time this bit of Bavarian brawn won’t be wedge-shaped sports car, but an SUV. The 5.11-metre-long XM is set to be BMW’s most powerful off-road vehicle to date and also the most horsepower-packed ride from M. According to the high-performance manufacturer, the vehicle can reach speeds of up to 270 km/h and will go on sale in April 2023 and cost upwards of €170,000 at home in Germany. The engineers at M have also opted for a d…