This seems like alot of work. Just to let you know, I have two Subaru parts cars at my boss' ranch.
One is a first gen Legacy, the other is a first gen Impreza [GC]. Parts interchange is basically the same from these cars to the GDs [02-07 Imprezas]
I've put a Legacy LCA on my Impreza, vice versa, I have a GD WRX sway bar on my GC, etc etc - they are all the same parts. The only difference should be the STi hub, which as you know, are 5x114.3
Let me know if I can help you out with parts measurements, etc