I am working on the same thing. I am going tonight to look at relacement subs. I will let you know what I find. In the mean time get busy removing the sub box in the trunk. It has four nuts holding the large black box to the rear deck inside the trunk. You will need a ratchet and a socket extention at least 10" long. Not sure of the socket size, but I can check tonight. I had to cut the wire going into the sub as there was no connector, but yours may be diffrent. Remove the WHOLE BOX and the sub is removed from the top, not the inside. Avoid the junk yard on this one! I will have the sub specs tonight and let you know what I find.
GL, Jason