Well that's a tricky one...
Swapping the Legacy Turbo's EJ22 into the Impreza is for the "Conversions" forum and the T3/T04 upgrade for the EJ22 is really more for "Other Factory Turbo" (ie. this forum).
I thought you were talking about turboing the N/A EJ22 that came in the aforementioned Impreza, thus my suggestion. Now that I know what you are talking about, I'd say this forum is quite appropriate for the question.
Shane -- http://www.warpthree.com