Just wanted to ask a question. I have a 03 gti and wanted to know if its possible to swap faces with an a3. I've heard that they have the same body.

Faces? Do you mean grille or do you mean bumper, lip, etc?

Yeah the hood, bumper and the side panels or whatever there called. The way people swap between jettas and gti's.

Well, they would be correctly referred to as the:
Hood
Bumper
Lower Lip or Front Valence
Right and Left Front Fenders

I suppose that, if they are truly the same body, that you could do it with a little tweak here and there. It would be most important to see if the fenders would line up well with the leading edges of the doors.