The 2015 WRX STI is powered by a 2.5-liter turbocharged/intercooled 4-cylinder BOXER engine that employs the Dual Active Valve Control System (Dual AVCS). The engine, which is exclusive to the STI model, produces 305 horsepower (SAE) at 6,000 rpm and 290 lb.-ft. of peak torque at 4,000 rpm.
The WRX STI engine is teamed exclusively with a specially reinforced 6-speed manual transmission, which includes an STI short-throw shifter in the Launch Edition model. Incline Start Assist can momentarily prevent the car from rolling backward when being driven away from a stop on an incline.
The Subaru Intelligent Drive (SI-DRIVE) powertrain management system allows the driver to tailor the car’s driving characteristics by choosing from among three selectable modes – “Intelligent,” “Sport” and “Sport Sharp” – using a rotary dial on the center console. SI-DRIVE alters vehicle performance characteristics by regulating the engine control module and by fine-tuning the electronic throttle control system.