The Ford Explorer remains unchanged for 2013, with some slight trim changes and the addition of a new engine option. It is a crossover with a unibody structure and road-biased demeanour. The Explorer is now available with a turbocharged 3.5-litre V6 model, in addition to the 3.5-litre V6, both engines mated to a 6-speed manually-shiftable automatic, with the base model getting front-wheel-drive and the rest getting full-time all-wheel-drive with no low-range gearing. There are four trim levels. The base model features include cloth upholstery, manual a/c, basic Ford SYNC with 6-speaker CD/MP3 stereo, 18-inch wheels, three-row seating, keyless entry, cruise control, capless fuel filler, power driver's seat, adjustable steering wheel, common power options and more. Available features higher up the trim levels include intelligent access with push button start, three-zone auto a/c, remote engine start, power liftgate, power-adjustable seats and pedals with memory, leather, heated and cooled front seats, MyFord Touch for the Ford SYNC touchscreen, 8-speaker stereo or 12-speaker Sony audio system, Bluetooth, 20-inch polished aluminium wheels, dual moonroof and power-folding third-row seats. The top Limited can be outfitted with further options such as HID headlights, rain-sensing wipers, adaptive cruise control with auto braking and the automatic parallel-parking system. The front-biased all-wheel-drive Explorer has an electronic center coupling that controls the torque split between the front and rear wheels, and acts as a center differential. Standard off-road electronics on AWD models include hill-descent control, hill-ascent assist, four-wheel electronic traction control and a standard "Terrain Management" system that varies drivetrain and ESP characteristics for different conditions. Standard safety features include dual front airbags, side and curtain airbags, Roll Stability Control, stability control and Curve Control. Other optional safety features include inflatable rear-seatbelt airbags, blind-spot monitoring with cross-traffic alert, and collision warning with pre-crash brake support.