i'm assuming its a mk5 xr3i?

you could use your existing inlet manifold with either a frst fuel rail or i'v also heard you can use a 8v astra gte fuel rail. not so sure on injectors. i am personally running biege injectors whilst i run it in but these will need to be upgraded b4 i get it mapped. what to i dont know.
AVA in glasgow turbo charged a mk3 fiesta zetec and they ran the standard management on its own with a injector driver running 4 additional injectors. this kept wiring very easy.iirc it was producing 280bhp. hope this helps.