It won't be cheap.
200 at the crank or wheels?
What's your budget?
I'm assuming you have a mtx?
Start with an intake, header, and exhaust. Best to buy all this stuff used off an SVT. SVT intake, header, and flex are the best you can get for the car and will look stock unless someone really k ows what to look for on a focus. People are always selling them on the buy sell trade forums for pretty cheap.
With a tune, that should get you maybe 20 extra hp to the wheels for about a grand once you buy everything you need along with the swap.
After that you are looking at cams, shaving the head, and things that cost lots of $$$$.
It's very expensive to get a zetec to 200hp na and in most cases it isn't a streetable car. That's why most people go FI.