The Sti turbo is either the vf39 or vf43 as stated above by wrxman420. Another turbo you could look at is the vf34. It spools pretty quickly and is great for a daily driver. Forced performance makes some good ones. im waiting on a few payckecks and im going to order the FP EvoIII 16g. So just look around and get information. Theres a sticky on this site that list a ton of different turbos, i believe its under the FAQ's section.
P.S. Dont rush into things, tuning and modding a car isnt something that should be rushed. So save some money, go to stage 2 and see how you like that power gain.