You would have to source the shifter, cables, pedals, etc from Europe but I'm sure the swap could be done. Check out FocalJet.com where several people have switched from auto to manual.
If you want more power google FSWerks. I'm sure Randy and Vic can provide what you want from a reflash to a full turbocharger kit.
FYI: If you didn't already know. The TC engine has been used in the Focus since 2005 adn the 2.3 L version started in 2003. I think the auto transmission is the same one that has been used since 2000.