2012 Subaru Impreza--five-door driver side

That leap in fuel efficiency is due in no small part due to the new, 2-liter Boxer engine, which provides a 10 percent fuel economy gain compared to the outgoing 2.5-liter engine. As with any give, there will be a little take: you have only 148 horsepower to play with in the 2012 Impreza, compared to the 170 hp found in the previous model year.