Here's how I installed my speakers.

1. Remove the rear seat entirely. Remove the bottom cushion first, and then pull off the rear seatback. There are three nuts. Two are on the bottom near the wheel wells, and the third one is under the center armrest.

2. Remove the first aid box. It's held in only by a couple of screws.

3. Slide the shelf towards you. If it doesn't move at first, don't worry. Pull harder. It might take some force!

4. You can put some Dynamat or similar material on the metal under the parcel shelf. (I highly recommend this, since you have it disassembled anyway).

5. Use something sharp to trim the holes. Heavy duty wire cutters work great.

Installation is the reversal of removal.