I'm a fan of most diesel engines. That's beside the point though.
What I'm getting at is, like the others have said, you will need to replace pretty much everything underneath the bonnet, including fuel lines, tank, pump, filters etc.
If I was in your shoes and the problem is as big as you say it is, then I'd be more inclined to try and pick up a 1.8T (full car) and then swap the bodykit and all the other gubbins over as it will be the easier way to do things.
You'll need to swap clocks, looms, and all that stuff as well.