From a previous post (I think it was mine!), someone mentioned trying to change the rear speakers was a waste of time because you don't have the "depth" to provide quality sound.
Another thing they pointed out was that most of the sound should come from up front (e.g., movie theaters), not rears...unless you've got one of those big subs taking up trunk space.
Don't take my word for it, let the real gurus add their two cents...good luck! I'll keep an eye out to see what others experience....
