What is the easiest, most reliable way to add about 40 horsepower + torque to a car?

I'm buying a 2012 Focus Se with the Sport package and 5 speed tranny. Looking to add about 40 hp to the base 160 hp 2.0 4 cylinder. I'm looking for easy and bulletproof, no twitchiness. Is it as simple as intake, exhaust, and ECU reflash? Thanks for the ideas.