I've got a supercharged 2.0 blacktop in a mk4 fiesta. Almost the same job in terms of fitment. I cut and welded the inner wing so I could mount the focus engine mount on the osf. If u use a mk4 fiesta box casing, and just update the internals the rear engine mount and gearbox mount can be reused. Also this means u can use original driveshafts.
Run aftermarket ecu definately to save a massive wiring headache and to unlock some more power.
Matt