i made that post with my cell phone last night. i just wanted to add to it and give you a more in depth break down of what you need to make 200whp with the zetec focus.
all motor no nitrous, turbo, or supercharger
forged lightweight high compression pistons $400+
crower stage 4 cams or more aggressive if you can find them. will put peak power at or above 8000rpms $350+
dry sump oil pump and CFM billet gear for higher than 7400rpms
nastiest P&P head you can find. $1500+
oversize valves with stronger valve springs $500+
shave the head for as much compression as you can get $100
SVT header conversion $500
3 inch exhaust $100-$700 depending if you order the good stuff or get it made locally.
custom intake manifold or preferably individual throttle body setup. at the very least a FR intake mani with FR 70mm TB $600-$1000 depending on which setup you choose
very good tune and xcal3 $500
race gas only, the car will probably not be street legal
stock motor with nitrous
brand new bare bones zex wet kit that comes with bottle warmer, purge, lines, solenoid, and toggle switch. $500
RPM window switch $100
A/F cutoff switch $50
fuel pressure cutoff switch $50
xcal3 and tune $600
Supercharger on a bone stock engine
used powerworks supercharger should put you at 200whp.
look for a deal and get one for $2000
tune and xcal3 $700 or however much it is.
turbo kit on a bone stock engine
used complete turbo kits sometimes get sold on this site for as little as $1500. a bone stock zetec can hold 250whp easily and if you build the motor you can keep pushing the power higher with a turbo kit. you are sorely limited with nitrous, all motor, and superchargers. tuning costs the same for turbo as it does for supercharging from Tom.
im sure i left out alot of things that are needed in my lists there but you get the general idea of what it takes to get there depending on what route you decide to take.