The M5 is equipped with a 4.4-liter twin-turbo V-8 making 600 hp and 553 lb-ft of torque. M5 Competition models get a power bump to 617 hp, while the M5 CS gets 627 hp. EPA fuel economy ratings are 15/21 mpg city/highway with the standard eight-speed automatic transmission. We've tested an M5 reaching 60 mph in as quick as 3.0 seconds. Even without its available super-sticky ultra-high-performance tires, the M5 CS rocketed to 60 in just 2.6 seconds...