I have a 2001 ford focus ZTS, how can I upgrade its performance?

My 2001 ford focus ZTS has a 2.0L DOHC Zetec engine and I want to increase its performance, what would you upgrade, install, replace, etc?

Added (1). its a 2001 ford focus ZTS Zetec-E engine if that makes it less confusing.

Nothing you do to that is going to give you any good performance because the car was not meant for performance anything. Even if you put full bolt-ons on it (exhaust, downpipe, headers, intake, tune) you MAY be at 140whp which is nothing. By todays standards and you would still be slower than pretty much any modern car.

Other option is to turbo it but without a deep knowledge of the inner workings of your engine and how to properly do a turbo setup you will most likely blow the motor up if you go that route.

BOTTOM LINE: Your car isn't made for performance and any performance mods you do to it will not only be a waste of money but will hurt your resale value as well. If you want a performance focus look at the SVT for a little more kick.

Thank you MattM i'm not much of a car guy but knew my focus didn't have much room for improvement and wanted a second opinion. My stock exhaust needs to be replaced and I was thinking of replacing it with a catback exhaust system with 4-1 headers what are the pros and cons? What would you replace the exhaust system with? Also my steering wheel shakes when I brake at high speeds, are my rotors warped?