I tried this myself and gave up. You can't just drop the speakers since they are mounted from the top. You can't remove the speaker grills because they are mounted to the rear deck carpet (at least that is how it looked).
I didn't want to start removing the whole back end. If there is an easier way please let us know.
you do in fact have to take out the whole back end.. its a royal pain, and took me a while to do and more then likely you will have to use shallow mount speakers because of the bars that go to the trunk lid
Haha! im in the process of doing it right now actually, and i ran into a problem with my speakers being to big and they hit the bars he was talkin about before but what i did was rip the original speaker off its frame and glued my new speaker into it and they mount quite nicely now! But im trying to get the deck back on....