What is the most efficient way to increase horsepower in a Ford Focus?

I am looking to upgrade my Ford Focus and increase its horsepower. What upgrades and modifications would you recommend for this specific model?

One of the easiest and most cost-effective ways to increase horsepower in your Ford Focus is to install a high-flow air intake system. This will allow for better airflow into the engine and result in a noticeable increase in performance. It's a simple modification that can be done at home with basic tools.

Another great option for increasing horsepower is to upgrade the exhaust system. A high-flow exhaust system can help your engine breathe better and produce more power. Make sure to choose an exhaust that is designed specifically for your Ford Focus for optimal performance.

If you're willing to invest more, you can consider upgrading your engine components such as the camshaft, headers, and fuel injectors. These modifications can significantly improve horsepower, but they require a higher budget and professional installation.