Duratec HE are in Mk3 mondeos and Fiesta ST's. If it's a budget build, I'd go for a 2.0 focus, strip it and go have some fun. When it breaks parts are much cheaper and modifications will be cheaper £ per BHP.

If you've got more money to spend then ST170 with a set of throttle bodies. They are dog slow and unreliable with the VVT and dual stage inlet.