The GMC Sierra 1500 comes in six different drivetrain configurations and one of five distinct body styles - regular cab with a long or standard bed, crew cab with a short or standard bed, and double cab with a standard bed. Beyond that, the 1500 can be equipped with a number of engine options that include a 4.3L V6 that that makes 285 horsepower, a 2.7L turbocharged 4-cylinder that produces 310 horsepower and 348 pound-feet of torque, a 5.3L V8 making 335 horsepower and 383 lb-ft of torque and finally, a 3.0L inline-6 cylinder turbo diesel capable of 277 horsepower and 460 lb-ft of torque. All 1500 and Sierras come with the option of 4-wheel drive except Denali where all-wheel drive is standard. Maximum tow ratings top out at 12,200 pounds when properly equipped. Trim levels for the 1500 come in four different flavors. Sierra, SLE, SLT and Denali. In standard Sierra trim, the Sierra is fairly basic with automatic windows and door locks, air conditioning, Bluetooth, a USB port and Teen Driver Safety suite as standard equipment. SLE versions add OnStar, heated exterior mirrors, a leather-wrapped steering wheel and an 8-inch touchscreen audio system with six speakers. The SLT trim includes heated leather front seats, steering wheel mounted audio controls, a remote starter, dual-zone climate control, power adjustable pedals and power-folding mirrors. Denali versions come in only one trim level and in crew cab and short-bed. Regardless of bed-length, the Sierra Denali includes an 8-inch color touch screen, 10-way power driver seat, heated driver/front passenger seats, a rear-camera mirror, a surround view camera system, MultiPro tailgate, power retractable side steps and wheels up to 20 inches in size. The Denali also comes with a unique grill and other selected trim. GMC's AT4 off-road model includes a 2-inch lift, off-road Rancho shock-absorbers, a standard V8 with 4-wheel drive and special tires for back roads. Available safety equipment includes front pedestrian braking, forward-collision alert, rear cross-traffic alert, lane-keep assist with lane-departure warning, automatic braking and lane-change alert with blind-zone alert. However, more common items such as a rear seat entertainment system, a navigation system, wireless mobile device charging, a remote locking tailgate and a sunroof are also available on the Sierra.