The 2018 Maserati Quattroporte comes standard with a 3.0-liter twin-turbo V-6 rated at 424 hp and 428 lb-ft of torque on the S and S Q4 models. A 3.8-liter twin-turbo V-8 with 523 hp and 524 lb-ft is only available on the range-topping Quattroporte GTS. Both engines come paired exclusively to an eight-speed automatic transmission. EPA fuel economy ratings are 1623 mpg cityhighway for the Quattroporte S and S Q4, and 1522 mpg for the Quattroporte GTS.