Im doing mine for 1k minus tranny.
The main problems as far as cost is the downpipe and crossover. The other stuff can be had cheap, like the powerlogs and other things. If you can find someone to make your downpipe and crossover you are set for a lot cheaper build.
My turbo kit was sub 2k. Just look for deals on used low mile kits. Although be careful because some of the kits ive seen go up lately are beat to hell.
+ Hes doing an ebay turbo that right there drop price dramatically.
You need an STI.
I was unemployed all last year. The only reason i got some cash is because im in school. Oh well next year right? I just picked up a gen v so i think i might go twin charged.