I DO NOT KNOW FOR SURE, BUT IF I HAD TO GUESS I WOULD SAY:
Transmission (you said 2005 STI?)
Rear Diff (you need a 3.90 final drive for the 2005 box, but your car should already have this )
Driveshaft (see if an auto DS will work for you)
STi Shift linkage (I think the 2008+ chassis requires longer linkage I heard?)
"Pull style" slave cylinder
"Pull style" clutch kit for STi
STi Clutch fork
Other than that, your axles should be just fine.
But as I said, I'm only speculating. Make sure when you complete the swap you post up what was required so we can all learn!