That would be the rear speakers, that sounded like they were playing
through a bucket of mud.

It was not as hard as I thought.
The entire rear pieces do not need to come out.

I'm not sure if people have posted this before without taking
the entire rear out. You can undo those little plastic
pull pieces (not sure of the names), the B and C pillar covers
are just one screw. This is after taking out the seats (BTW, what
is that little cord with the pull ring on it?). The big black plastic
panel has only one screw also, and a lot of those pop things.
Start toward the front seat and pry/pop those things off.
Oh, the seat latches you do not have to take off the black
plastic trim.

There is more than enough room to reach over the plastic panels,
remove the old speakers and install new ones. I chose to solder
on new clip connectors that match the new speakers.

I am using a low end Boston Accoustics. So now there are 6 of them
in the car and they are very clear, but I can tell the radio itself
does not have the power to really drive them good. I hope to
install the amp this coming weekend.

I'm very excited to get near the end of this. I don't know yet
if I chose wisely on the BAs. I have infinity in the honda but they
are very bright, so I went with the BAs that I had put into my wife's
VW (ended up trading that POS with a brand new HD/XM radio too).
The thing is I didn't use low end BAs in her car. So I do not know
yet. My aim was to get a radio that is both loud and clear
but not as tinny sounding to my ears as my honda. Although I have
to wonder if in the honda which has almost no space for the base
to reverberate behind the speakers was the actual problem, not the
infinity speakers.

Whole rear swap was only a couple of hours and that is good time
as I do not hurry myself when I am working at home.

I will be posting more results as I finish up.