I took out the map shelf and I mounted speakers
in the upper corners of the front foot wells.
I found an existing hole that comes out in the corner
of the engine compartment and I used a 3" long screw
to basically hang the speaker. The screw went through
into the engine compartment and I put a lock washer and
nut on it and tightened it down. I also put silicone
sealant around so it so no water can get through the firewall.

The speakers fit nicely on both sides and are high enough that
they don't get in the way of peoples feet.

I left the other screws on the inside and just tightened the
the nuts down. With the bolts sticking through the speakers,
they dig into my carpet just enough to hold the speakers in
place. I have 5.5" pioneers in the front.

I also put 6x9's in truck speaker boxes an they sit right behind
the front seats on the floor. I left plenty of extra cable on them
so when I do put somone in the back seat, I can just move the speaker
boxes into the the back.

I can take a picture later today when I get home if it would help.

I really didn't want to cut the door panel either.

Good Luck!

Karl