1800 is a decent start, but be prepared to AT LEAST double that.
I think I'm at 3700.00 so far, and I still need a clutch and LSD(optional)
oh and oil lines & fittings, drivers side motor mount, and i'm sure something else will come up. Mind you, i've found GREAT deals on most of my parts.. if you're paying retail for all of this, the price is going to jump and jump quickly.
check out my thread, it will help you get started on what you need and what is suggested. http://www.focusfanatics.com/forum/showthread.php?t=266902
ohhh yeah, you can't forget about tuning! that's another 550 if you are working with Tom, and probably more from other places.
as for power, Toms kit at 10 PSI on a stock motor will put you at about 200-220 WHP
I think he said you would need to run 17-19 PSI for 300whp+?? i'm sure he can clear that up. (I have his kit BTW.)
I suggest you really read up in this forum, there is a TON of info you will need to know before you get started.
My advice to you is to plan out your build before you buy anything.. make sure you are set on what you want to do. I thought
i knew what i wanted to do and ended up spending 500+ bucks on crap i'm not even going to use.
Take your time and have fun!