The rear-wheel drive 550i features a 400-hp 4.4-liter, twin-turbo, V8 engine, with the choice of an eight-speed automatic or six-speed manual transmission. Standard features include leather upholstery, dual-zone automatic climate control with active micro-filtration, a 16-speaker AM/FM/CD audio system, HD radio, Bluetooth, 18-inch alloy wheels, voice-activated hard-drive based navigation system, and iDrive control system with integrated owner's manual. Safety is provided by six airbags, active anti-whiplash front head restraints, electronic traction and stability control, anti-lock brakes, tire pressure monitoring, front and rear parking sensors, BMW Assist telematics, and bi-xenon adaptive headlights. Debuting on the new 5-series, an optional Park Assistant system will steer the car into a parallel parking space.The 550i has been completely redesigned for 2011.