going to answer your question first, then post some other comments below that you might find valid. The door comes off easily. pop off the panel around your door handle (on the inside) and put it aside, use a screwdriver and pop out the control panel (where the lock and window switch is) on the arm. remove the lock harness and the window harness. set panel aside. now... this is from memory... but i think there are two screws under the arm rese area that need to be removed, you can see them from below.
at this point just check around for more screws... there are none around the outside.. they are all around the arm rest area/panel area.... i THINK there was one inside the area where the control panel is... cant recall though. lemme know if you need more information and i'll pull mine off to give ya a step by step if needed. anyhow, once its out you need to remove either 4 or 6 torx screws (allens work too) and then just undo the connector and remove the speaker, swap in the new one, reverse steps.
the 460 is not that bad for a stock system, one of my favorites. however mine had a MASSIVE issue that i corrected later by accident. mine REALLY sucked balls... massivly, ZERO bass, horrid volume and was REALLY depressing. full volume, at 80 mph i couldnt hear it with the windows down... anyhow
i was doing small upgrades to my power system to support the stereo i was going to install, i added a terminal battery block (for use of easily adding an amp line) and the combo of resetting the system or the battery block somehow resurrected my system... bass finally came alive (impressive for a stock system) and volume was respectable. it finally shined as a solid stock system for a change.
if you are having issues, give this a shot (reest the system at lest by removing the positive lead from the battery for bout an hour or more, then reconnect) and see if you get any improvement... i did. and i am debating going back to stock to save weight (massive amp, and sub). anyhow.
hope i hvae helped somewhat.
Torinalth