Looks like its fairly straight forward, they have a YouTube video showing how it is installed on a Pontiac Vibe. Don't see how it would be that different on the focus.
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)