It is absolutely impossible to run negative offset on a Subaru without some serious surgery. I'm not positive if you can even switch between '04-'05 hubs to change the bolt pattern, as the mounting points could be slightly different.

 

I assume BAN is speaking for the good of your car (meaning the gods of Subaru will not come down & smite you if you mount some reverse offset Daytons on your car - you can do it - although they probably should...). But either way, are you looking for 5 or 6 inches of lip? B/C if you are just looking for 1.5-3 inches of lip, then you could get wheels as we discussed earlier. I suggested swapping to 05 hubs b/c 5x114.3 is used an almost all other 5 lug Japanese cars & some domestics as well, and so you will have a wider selection of wheels.

I imagine you could just swap the hubs w/ an 05 STi, but I think you would be the first to do it.