How to increase the horsepower of a Ford Focus?

I have a Ford Focus and I want to make it faster. What are some modifications I can make to increase its horsepower and overall performance?

Adding a cold air intake and a performance exhaust system can increase horsepower by around 10-20 hp.

A tune-up and installing high-performance spark plugs can also make a noticeable difference in horsepower.

Invest in a turbocharger or supercharger for a significant increase in horsepower, but be prepared for a higher cost and potential engine modifications.