You cant find a Duratec in ANY (standard) focus in the UK yet, it will be in the mark 2 when it comes out!, it is in the Mondeo and in the later rangers. The duratecs have been in the US focus's for a few years now.

As said the RS and ST's foci's arent duratecs just been badged as one! damn fords

Supposdly they are the new engine to tune, but time will tell