The Duratec engine in the 2005+ Focus's is among my favorites. It's a rebadged Mazda MZR engine so there's quite a lot you can do with it. I'm a GM guy but I'd really like to toy around with those engines in a "Let's poke it with a stick and see what happens" kind of manner.
During my research, I came across the fact that Cosworth, on of my favorite aftermarket companies, makes a plethora of parts for the 2.0L and 2.3L duratec and MZR engines.
Cosworth Crankshafts:
http://www.cosworthusa.com/store/pc/viewCategories.asp?idCategory=24
Pistons, rods, and bearings, OH MY!
http://www.cosworthusa.com/store/pc/viewCategories.asp?idCategory=23
cylinder heads, valves springs, and camshafts, etc.
http://www.cosworthusa.com/store/pc/viewCategories.asp?idCategory=25
Shop around the website. There's more, I guarantee you.
Other companies I'd trust with making parts for the engine include Focusport, now called FSWerks:
http://www.fswerks.com/
If you want to turbocharge the car, you best bets are either the FSwerks turbo kit or trying to find a wrecked Mazdaspeed 3 or Mazdaspeed 6 to strip the engine of it's turbo specific parts.
For superchargers, I think you're SOL. The only company I know of that was working on a kit was F2 Focus and they seem to have gone out of business.