I didn't see many good pictures of how this can be accomplished so I thought I would throw a few up to encourage others to try it. I'm skipping the whole process of getting to the panel that the speaker sits in, but you basically have to strip the rear of the seats and all plastic wall panels. Once you are there, pull and remove the black plastic speaker panel and remove the existing 6.75"-nothing-commercial-will-fit-here-easily speaker. I used the template that came with my Pioneer 6x9s to layout the hole I would need to cut in the panel. I traced it out and cut it with my jigsaw, so it looked like this:


I had to do a bit of grinding on some of the plastic ribs in the panel to make the speaker sit flush. I used the metal screw clips as you can see for tighter screw in than just through the plastic. Install the speaker and run the speaker wire, I soldered the old speaker plug onto the new 6x9 for a nice factory look. Here it is from the rear ready to install:


And with the panel reinstalled, speaker plugged in, tested and working:


There is plenty of depth in both directions for the 6x9s and my speaker covers fit back on and everything is stock and clean. There you go, easy!

 

do u have any after pictures with all the interior put back together?

 

Sure, but there is nothing to see:

 

Clean install! I also try to solder contacts that I work on, except on weather-tight factory connectors. More resistant to corrosion and more secure than spade terminals. Thanks for sharing.

 

wow, that looks great. Clean as it gets, good job!

 

CLEAN!! Good work, man!

 

There are many 6-3/4 speakers available, is it the depth that is the issue?

I will not be doing the rears and still drive them with the HU for rear fill. The front will have Polk components and an easily removeable Xterra's 8" fosgate box for bass, both will be driven via a small amp

 

This is true that there are a few 6.75s out there, I just know that when I searched at Crutchfield, their "vehicle research" stated they did not carry any 6.75 which would not require bracket modification.

I went with the 6x9 because I had them and they have tiny bit more surface area (sd) than the stock size. Depth is no issue in either direction whatsoever, heck you could probably mount an 8" or 10" sub back there...(hmmm...) You are correct that the most audible difference in sound will be gained by going to components in the front. As a side not, I also replaced my front door speakers and headunit so it sounds waaay better all the way around!