With basic tools and a little patience, you can accomplish this job in 60-90 minutes. I would like to mention that depending on 'how much' stereo you want (sound quality improvement and/or raw power upgrade) should factor into your speaker choice. The amplifier in the factory head unit is barely adequate to power even after market brand name speakers. Consider replacing the factory speakers with the 5x7s/6x8s of your choice knowing that you will probably want more power by means of an after market head unit or amplifier using a line out adapter.
I was hoping that the stock head unit would have enough power to keep me happy until next year when I can afford a full blown upgrade with high end components, alas it was not to be. Now I am taking the extra step to install an amp I already had to power the JL Audio 6x8 coaxials now in the car.
FWIW, don't bother with the hassle of replacing the rear speakers unless you are adding more power. The factory head unit seems to bias the power output at least 75% to the front, with the rear only providing the lowest sound levels.
Start by pulling off the triangular trim piece at the top corner of the door. A small flat blade screw driver does the job, but you can get a hard plastic trim removal tool from Amazon if you are paranoid about scratching the plastic.
Pop off the power window switch trim panel.
Pop off the door handle trim piece.
Pop off the door lock post trim piece.
Now get your torx bit in your ratcheting screwdriver and remove the bolt from behind the door handle.
Pop off the window switch panel to give access to the hidden 4mm bolt.
Pry out the trim panel to the right of the window switch panel in the middle of the door panel to access the 2nd bolt, and remove it with the same bit as the door handle bolt.
There are 8 hex head bolts, I think they are 4mm, sorry can't recall exactly, 2 on the side of the door near the door hinges, 3 on the bottom of the panel, and the 2 on the end of the door near the door latch under 2 plastic covers.
So that's only 7 bolts, where is #8? Behind the window switch, I couldn't see it at first and couldn't figure out why after removing all the other bolts why it didn't just pop right off with a little upward pressure? I have an old back seat bottom from a '77 Tbird that I use for working on cars in my drive what that I used to supporth the panel once I got it off. No need to unhook the cables for the door latch mechanism.
Now you can finally see the stock 6x8's and remove them. Replacements will bolt right in, no need to replace the stock spacer on the door. I only had to remove the mounting tab that was on the very end of one side of my coaxials, the 4 bolts to hold the speaker in align in the standard locations. Do not over torque the bolts when replacing your speakers!!
Do yourself a favor and order the Metra speaker harness adapter from Amazon, it's *exactly* what you need and make the job easy.
Make sure you test your speakers before bolting the panel back on.
The process is the same for the driver's side except there is an electrical harness connection for the power mirror control switch.
And that's all there is to it, except of course realizing that even after all that work you really need more power! I will cover my amplifier installation in another thread.