Well, go look at a manual. The speaker is bolted on the inside to the door. The grill is screwed on from the inside face of the panel. You pop the grill, you break it. You need to remove the door panel to unscrew the speaker.
The grills are not able to be pulle dout. They are a part of the reardeck.
You have to pull the trim, and rear seats out. There are a bunch of clips holding the deck in. Those have to go. There are screws holding the deck down if you lay in your trunk and look up.
It's a total pain in the ass.
btw If you put subs in your truck it is well worth it to make the trunk airtight to the deck. Otherwise every time your subs hit the rear speakers will horribly deform.
Also the 3" speakers in the front dash are actually not 3" speakers. They are somewhere between 2.5-2.75".They are also the largest pain in the ass to swap out. They're hard to get to and you have to modify them heavily to hold 3.5" replacements that are worth a crap. It's easier to just leave them and cut the wires going to them.
The stock tweeter locations can hold larger tweeters in the door post with light modding. The front speakers are 6.5" and hold larger ones easily.
3.5" infinity referance speakers
6.5" infinity kappa's w' the 1" tweeters
Kicker sbm8's in the rear deck
2 2004 Kicker 10" L7's in the trunk
That's how I went. Rear audio sucks ass... Stage in front and bass is omnidirectional. Location doesn't matter so much.