I am trying to purchase new front struts for my 2004 Impreza 15I hatchback, 4WD 1500cc. This is a Japanese model and I'm trying to figure which struts from the U.S. would fit this model? I think it may be the TS but can someone confirm?

Try http://opposedforces.com. There is possiblity to look if particular part used for other subaru models (US and European but no Japanese).