Breaking down the plug-in hybrid powertrain, the 4.4-liter twin-turbocharged V8 will deliver 577 horses and 553 lb-ft of torque on its own. It will be paired with an electric motor generating 194 hp and 206 lb-ft of twisting force. Completing the hybrid setup is a battery pack with a usable capacity of 18.6 kWh – a smidge lower than the XM’s 25.7 kWh figure.
However, the upcoming M5 will get a significant weight penalty, allegedly tipping the scales at about 5,368 pounds. For reference, the standard 5 Series (G60) comes in at 4,041 lbs only, while the all-electric BMW i5, supposedly heavier because of bigger batteries, is lighter by 121 lbs than the M5.