2017 Porsche 911: The latest version of Porsche's iconic sports car, the 2017 Porsche 911, offers up some changes in its exterior dimensions while also offering some mechanical changes meant to improve the driving experience. There's more available power on tap in some models, as well. The four-seat 911 competes with other two-door sports cars such as the Chevrolet Corvette and Nissan GT-R, and it comes in Carrera, Carrera S, Turbo, and Turbo S flavors. Targa and Cabriolet convertible versions are also available.The Carrera has a 3.0-liter twin-turbocharged horizontally-opposed six-cylinder engine that makes 370 horsepower, while the Carrera S has a beefed-up version of the same engine that makes 420 horsepower. The Turbo offers a 540-horsepower twin-turbocharged horizontally-opposed six-cylinder that displaces 3.8-liters while the Turbo S puts out 580 horsepower. The 911 is available with rear-wheel or all-wheel drive and a seven-speed manual or seven-speed automatic transmission, depending on version. EPA-estimated fuel economy ranges from 19 mpg city to 29 mpg, depending on variant.Available features include navigation, adaptive cruise control, Bluetooth, satellite radio, and an infotainment/telematics system that includes a touchscreen, smartphone connection, and app suite.Available safety features include anti-lock brakes, lane-change assist, multi-collision brake system, and dual-front, front-side, driver- and passenger-knee and side-curtain airbags.The 2017 Porsche 911 starts at $89,400, not including dealer and destination fees.