I'm no expert, but, I was in the same position so I went for the zetec swap.
I'm using a 2.0 mondeo blacktop, PEC pistons and rods, Bosch green injectors, uprated valves springs, standard ford head gasket, omex 600 managment, the CVH t3 and manifold on an adapter plate, cvh efi flywheel.
You'll probably want a better gearbox than a std BC if you are aiming for 250bhp if you haven't already got one.

One thing I will say is what ever you think your budget will be, it'll be more. All the little bits add up. Boost pipes, sensors, water hoses, fuel lines, loom etc
There is a bit of faffing about trying to get water hoses, alternator and some other bits to fit but nothing major.