The heart of the beast, this twin-turbo, 3-liter, straight-six-cylinder engine more than impressed us in the 535i and 335i convertible. We can't imagine what it will do in the much-smaller 1 series. BMW has a few clues, such as 5.3 seconds to 62 mph. The engine puts out 306 horsepower and 295 ft-lbs. of torque.