Turbos!

[kernow_joe]

I've said it before and I'll say it again,
big boost != big power

its not all about pressure, my d-turbo was probably around 20ish psi and was as quick as my 6, (T25 turbo, 11mm modded pump et etc) its all about flowing the air, lots in lots out and lots of fuel in and burnt!!

but yeah in response to your original question td04 13t from impreza are the ones people fitted a lot, but there are many many other turbos you can make fit with a bit of searching