Buy yourself a dremel they run about $40-60, and then just cut the old speaker out of the harness. Once you cut them out just find a small thin board to fill in the gap (assuming you are replacing them with 6.5 speakers), and seal the board with silicon. If you are going to use 6x9, then the speaker should fit over the spacer and screw it down. The dremel is a wonderful tool for these small projects.