This may or may not help. On my 1991 deville, I had to remove the rear I call it headrest bar it was above the rear seats and the seat belts came thru it. It came out with me removeing the phillips screws holding the plastic covers for seatbelts then behind those were 10mm bolts the "bar" of headrests then came off the rear tray was held in by the 2 bolts was well. With the rear tray removed the speakers were held in place by a clamp that popped out with a little upward pressure. I did have to run new speaker wire when I replaced my speakers as I have never found out out to rewire the factory bose speakers to an aftermarket radio, but the factory speaker holders held the new speakers just fine.