The BMW 840i xDrive Convertible and M850i xDrive Convertible share a top speed of 155 mph, the M8 Competition Convertible has a top speed of 156 mph, and the M8 Competition Convertible with available M Driver's Package boasts a top speed of 190 mph. The 0-60 mph acceleration time differs by model, with the 840i xDrive Convertible clocking 4.6 seconds, the M850i xDrive clocking 3.9 seconds, and the M8 Competition Convertible at a blistering 3.1 seconds.
BMW AG preliminary test results. Actual acceleration results may vary, depending on specification of vehicle; road and environmental conditions; testing procedures and driving style. These results should be used for comparison only and verification should not be attempted on public roads. BMW urges you to obey all posted speed laws and always wear safety belts.