1998 toyota corolla, speaker upgrades

i have a 1998 toyota corolla and desperately needs an upgrade on the door speakers.  when i took the door panel off, i noticed the there are no screws to take the speaker off the door.....it seems as if the speaker is part of the adapter and the adapter is reivited onto the door itself.

any suggestion on getting the door speakers off?

how big does the drill bit have to be? when i put the spacer back in, do i just screw into the door?

right on forbidden.....big help, thanks.

New to this, will be upgrading my corolla 98 speakers as well, so wanted to verify:

"onto a piece of 1/4" mdf or abs and cut out a new speaker hol"

What r you referring to with "mdf" or "abs". Thanks.

no need to take off the weatherproofing...i just used a 1/4" drill bit to drill out the rivets and the speaker adapter just came off.  i jused a 1/2" thick mdf board and traced the old speaker adapter onto it and cut out a hole to where the speaker was going to go, then cut out the pattern that i traced, screwed on the new adapter using 1" long self tapping screws onto the door, wired the speaker, and screwd it onto the new adapter.....i'm using 6.5" pheonix gold octane r.  fits perfect.  i still have to cut out a hole for the tweets, thank i'm done.  not as hard as i thought, just take your time and don't rush.

i ended up using the stock wires.  i wanted to route new wires, but got lazy.