if their the same as my 96, you have to fold down the 2 rear seats, on each of it's lower corners, you take off a total of 6 screws,. 4 on the smaller section, 2 on the side of the larger one, u slide off the smaller one, then at the hinge between both of them, u gotta unscrew the on that holds the hinge in, it's a sideways one. then u can slide out the larger one but one thing, u gotta pull out the wall side first, the side u took out the 2 screws front, then u push the whole thing towards the wall, the one in the middle for the big seat is like a dowel stuck in a hole, so remember that, u can pull it strait out
then u will see after you take off the 2 erar seat panels one biig screw that holds down the actual seat, it's in the middle on the metal part of the car. the rest of the hinges must be removed to take off the side wall panels which are held in by 2 philip's screws, u will see a big square indent in the panel, and the side wall panels must be taken out to take off the rear deck to change the speakers. just to let you know. the rear deck u you push up and pull towards the front of the car, don't be afraid to break it, it won't come out unless you use some force.
By the way, this is for the coupe, i dunno if the sedan is the same.