The speaker size is 5X7 or 6x8, both will fit. The door panel comes off pretty easy. The top vertical piece just pull off with a firm pull. There is one screw under that. If you have power windows/locks, remove that piece. Use a flat screwdriver with some tape on the tip to prevent scratches. Once you pop off the switches, remove the connectors from underneath. The trim piece around the door handle also pops out, if you look carefull around the edge there is a little slot to pop it out. There are one or two screws there. That's it, now pull the entire panel UP and out, do not pull it straight out or you might break off the tabs that hold it in. Don't pull it completely off yet, disconnect that little light in the side of the panel.
If you have manual windows, the window crank handle comes apart into two pieces. Carefully pry the cover off and it swings out of the way, there is one torx screw in the crank handle.