Three 4Runner trims are available for 2010: the base SR5, Trail and Limited. The base engine, available only on the base SR5, is 2.7L 4-cylinder, offering 157 horsepower at 5200 rpm and 178 pound-feet of torque. The base engine on all other trims is a 4.0L V6 with an impressive 270 horsepower and 278 pound-feet of torque. The 4-cylinder engine comes connected to a 4-speed automatic transmission, while the V6 engine gets a standard 5-speed automatic transmission. The SR5 and Limited can get either rear-wheel drive or 4-wheel drive (part-time on the SR5, full-time on the Limited). Maximum towing for the V6 is 5,000 pounds, and just 2,000 pounds for the inline-4 engine. Standard safety features include antilock 4-wheel disc brakes with brake assist, stability control, traction control, anti-skid system, active front head restraints, front knee airbags, front-seat side airbags and full-length roll-sensing side curtain airbags. Toyota's A-TRAC system is standard on all 4WD trims, which can distribute driving force to any one wheel in contact with the ground, making rough driving much smoother. 4WD trims also get standard Downhill Assist Control. Trail trims also get Toyota's Crawl Control (CRAWL), which regulates the vehicle's speed in severe off-road conditions and Toyota's Multi-Terrain Select system, which allows drivers to manually adjust the 4WD hardware to suit their needs. All V6 trims come with Hill-start Assist Control (HAC), which provides additional control by keeping the vehicle stationary while starting on a steep incline or unstable surface. The Limited trim comes standard with an X-REAS suspension system that automatically adjusts the damping force of shocks when driving over uneven surfaces or cornering. Available as an option is the Kinetic Dynamic Suspension System (KDSS), which can disconnect the front and rear stabilizer bars at speeds below 40 mph for greater wheel articulation. Standard equipment on the SR5 includes 17-inch alloy wheels, fog lights, air-conditioning, cruise control, full power accessories, a tilt-and-telescoping steering wheel, trip computer and audio system with an auxiliary audio jack. SR5 trims with 4WD also get heated side mirrors with turn indicators and puddle lights, chrome roof rails and grille and a tow hitch receiver. Standard equipment on the Trail includes a hood scoop, a locking rear differential, Crawl Control, off-road tires, smoked head- and taillights, back-up camera, steering wheel-mounted audio controls, water-resistant upholstery, power front seats, a sliding rear cargo deck and an upgraded audio system with satellite radio, a USB port and iPod connectivity. The Limited trim adds 20-inch alloy wheels, Toyota's X-REAS adaptive suspension dampers, keyless entry and ignition, automatic headlights, dual climate control, an upgraded audio system with a six-CD changer and 15 speakers, a leather-wrapped steering wheel, leather upholstery, heated front seats and driver power lumbar support.