Yep, you may need to use a flywheel from a 2L, but the 04 STI clutch should work.
I used an ACT SB10-HDSS ... I really like it and it's been working fanastic for many years. I used an Exedy before this ("stage 1 HD" or whatever it was) and it lasted 6 months - which sucks assay because the 6mt is huge, heavy, and really annoying to take out. My driving style didn't change between them, maybe it wasn't making full contact, maybe something was off, who knows.
If you're doing it yourself, I have a transmission mount attachment for my jack you can borrow (or buy if you want).