The M5 features a high-performance version of the 5-series' 4.4L twin-turbo engine. It utilizes direct injection and BMW's Valvetronic system, which can vary intake valve lift to both save fuel and aid responsiveness. Horsepower is rated at 560 and torque is stated to be 500 lb-feet. Power is sent to the rear wheels via a 7-speed dual clutch automatic, while a traditional 6-speed manual is available as a no-cost option. With so much horsepower, acceleration is extremely strong, and the M5 is comfortably faster than many sports cars on the market. A single Driving Dynamics Control selector lets the driver click between Comfort, Normal, Sport and Sport+ modes that coordinate throttle and transmission response, steering boost, stability-control intervention and the Dynamic Damping Control suspension. 19-inch wheels and HID headlamps are standard, as is a high-performance audio system that includes both HD radio and a 6-disc DVD changer. Navigation, 18-way heated seats and 4-zone climate control are also included. "Green" features include a brake-energy regeneration system to charge the battery only when the brakes are applied as well as an "auto-stop" feature to save fuel when the engine is idle. The M5 includes great seats in all variants; in front they're widely adjustable and especially good for taller drivers. BMW's iDrive screen-driven interface comes in all 5-Series models, and it's been improved in recent years with more intuitive, streamlined menus and controls. The M5 includes dual-zone climate control, rain-sensing wipers, power heated mirrors, xenon adaptive headlamps, dynamic cruise control and other extras. Merino leather seats come standard, as does hard-drive navigation, a rear-view camera and park distance control. A Competition Package improves the M5's performance numbers in most every way, with sport exhaust and tuning adding 15 horsepower to the engine's output as well as revised suspension settings and tuned steering to improve handling and response and 20-inch double-spoke alloys.