It might not be nearly as powerful as the M5, but the 550i still produces a massive 440 horsepower. And, in fact, the 550i employs the same 4.4L twin-turbocharged V8 as the M5, and can be equipped with an eight-speed automatic or six-speed manual transmission.
With the eight-speed automatic, fuel-mileage isn't too bad for a high-performance V-8, delivering up to 15 mpg city and 22 mpg highway. The base 550i sends power to the rear wheels, while the 550i xDrive has all-wheel-drive.
The 550i has received minor updates in 2013, most notably the addition of a split fold-down rear seat as a standard feature. The interior has one of the best designs in the class. Though the driver and front-seat passenger have enough space, the same can't be said for rear-seat passengers.
Xenon adaptive headlights turn with the steering wheel, up to 15 degrees left or right, to better illuminate the road as drivers steer into corners. Adaptive technology is also featured in the taillights, which increases brightness depending on the amount of pressure applied to the brake pedal; those driving behind a 550i can tell if it's coming to a slow or abrupt stop.