Two different engines are available on the 2012 Toyota Tacoma lineup: a 159-horsepower, 2.7L 4-cylinder and a 236-hp, 4.0L V6. Both engines utilize variable valve timing to help provide both strong low-end torque as well as higher-rev passing power. A 6-speed manual transmission is available with the V6 as is a 5-speed automatic. 4-cylinder Tacomas are equipped with either a 5-speed manual or a 4-speed automatic. Just as with most other pickup models, the Tacoma is available in several different configurations so as to suit a wide range of uses. Regular Cab models come with two doors, with the Access Cab including a small backseat as well as rear doors that open 80 degrees for easy access; 4-door Double Cab models include 60/40-split rear seats that are comfortable enough for adults. Access Cab models also have fold-up rear seats, but add under-seat storage. All Tacoma models come with electronic stability control, anti-lock brakes, brake assist and an automatic limited-slip differential. With the available Off-Road Package, there's also Hill-start Assist Control and Downhill Assist Control, which help keep traction on steep slippery slopes or moderate speed and traction on steep downhills. Seat-mounted side airbags, roll-sensing side airbags and active front headrests are also included. The Toyota Tacoma X-Runner model features the highest-performance of the lineup and carries over with a number of serious performance modifications as well as appearance upgrades. The suspension is specially tuned for road performance, while there's a full body kit, hood scoop and special fog lamps. With the V6, it's claimed to accelerate to 60 mph in less than seven seconds, but there's even more performance potential on tap with an available supercharger kit, bringing output up to 304 hp and 334 lb-feet of torque. Base Tacoma models are quite simply equipped and don't even include power windows or locks. They do come with air conditioning and a 4-speaker CD sound system. Access Cab and Double Cab models get a nicer 6-speaker system, while including power windows and locks. Double Cab models also get a lumbar-adjustable driver's seat. Options on Access and Double Cab models include an upgraded 7-speaker stereo with iTunes connectivity, steering-wheel controls, a backup monitor system and an auto-dimming rearview mirror with Homelink universal transceiver. A Tow Package available on Access Cab V6 models brings tow capacity up to 6,500 pounds. Also available as a dealer-installed option is a TRD Big Brake system, which includes bigger vented rotors, aluminum 4-piston calipers and braided steel lines. The TX and TX Pro packages give the Tacoma PreRunner and 4x4 models a more aggressive, more off-road-capable look with special accessories and performance enhancements. The TX package brings the menacing look, with BF Goodrich Rugged Trail tires on 16-inch black alloy bead-lock wheels, special tube-side steps, a stainless steel exhaust tip and exterior graphics, while the TX Pro gets a special cat-back performance exhaust system. Both include what's otherwise offered as the TRD Off-Road Package, with progressive-rate front springs, an electric-locking front differential, Bilstein shocks, a larger stabilizer bar and fog lamps, plus a 400-watt, 115-volt powerpoint, sport seats and an overhead console.