Top Hats are the "Strut Tops".. you need the ones for the rear since the OE springs taper to the top. So, your '04 rear strut tops are smaller than the 02-03. Since the Eibach kit does NOT taper, you need the OE strut tops for an 02-03.
The Strut Top is what keeps the spring nice and tight between that "bowl" on the strut and your car. Diagram and part numbers from subaruparts.com
20370A $49.78 Strut mount-rear,right
20370B $49.78 Strut mount-rear,left
Someone, please correct me if he needs more parts than the ones I listed.