The 2010 to 2017 Ford Flex models are surprisingly spritely, quick, and comfortable and make for an excellent platform to put together a slick and aggressive street crossover build. While their squareish looks aren't everyone's cup of tea, the Flex crossovers, especially those rocking a 3.5L EcoBoost V6 under the hood, are more than capable of becoming brutal and powerful street machines that can still haul the family around safely and comfortably.