Removal of rear speakers on 2000 old...

you should be able to reach them from the trunk, if not there should be a way to detach the speaker covers in the back dash, I never had to remove a seat to change speakers

On a Oldsmobile Intrigue yes you have to remove the back seat to access the speakers, I just changed mine it's not that hard. First remove the bottom part by pulling the two release rings (1 on each side) where the seat meets the carpet. Next in the trunk pull the seat back releases to fold down the seat backs, plus unclip the release cables from the trunk (they come out with the seat back) Then there are 4 10mm bolts on top and 2 10mm nuts on the bottom remove them and take the seat back out. The rear deck has the speaker covers fastened to it so the whole deck needs to come out. There are 3 push pegs behind where the seat back was remove them, then all you need to do is push down in the back corners of the deck - there is a tab from the molding that goes into a slot in the deck, free them there and take the deck out. the speakers come out the top. It took me about 1 1/2 hrs to change speakers, after I paid for instrucions I'm sharing ; )