Looking for something a bit more powerful and more substantial than the WRX? Go for the 300 horsepower WRX STI. Serving as the high-performance flagship, the turbocharged four-door sedan is the ultimate form of the WRX line. Instead of a 2.0-liter flat-four, the WRX STI has a more potent 2.5-liter flat-four engine that is mated solely to a six-speed manual gearbox. Like the WRX, it has selectable driving modes, a touchscreen infotainment, a high-tech multi-info display, as well as sport bucket seats.