As standard, the Flex has a 3.5-liter V-6 powering the front wheels. That engine returns 287 hp, 254 lb-ft, and gets 16/23 mpg city/highway. All-wheel drive is optional. The AWD Flex can be made into something of a sleeper with the optional twin-turbo 3.5-liter V-6. That engine produces 365 hp and 350 lb-ft of torque, which we found to feel slightly laggy but entertainingly powerful. Efficiency doesn't suffer terribly with the turbocharged engine, dropping to 15/21 mpg city/highway. Every Flex has a six-speed automatic transmission.
