I just added a set of Audiobahn AS40Q 4" 2-way component speakers to my 84 Aspy. These are really nice since you have the option of removing the center tweeter and remotely mounting it. I have it mounted in the center of the speaker right now but am planning on a remote mount soon. Another plus is the Butyl Rubber surround. Unlike the "foam" surround that most speakers have, the Butyl rubber will not break down and deteriorate.
I just love component type speakers. You can really tailor them to your liking. I will post a picture of the installation once it is complete.