Had another thread about this seeking some advice, figured when I did it myself I'd photograph it and post the images for anyone else looking to install speakers and tweeters in the panel.
Remove the panel... I didn't chronicle this since so many resources out there already. I used this YouTube clip which was very helpful.
First thing I noticed was that the factory speakers included a tweeter already (to the right of the 6.5" speaker), held in with a screw in the back. You'll have to remove the plastic speaker housing which is held in with I believe 3 bolts, and black glue to remove the screw... I opted for the lazy way out and simply cut the wires.
When I opened it I was expecting to find 2 wires, instead found 4, which was confusing at first, until I realized that the extra 2 wires, didn't connect to anything. The speaker and tweeter both fed off the same pair of wires. The photos are for the driver side speakers, first shows the wires, the second shows inside the plug and how there are only 2 pins not 4.
The wire colours you need to work with are
Driver Side: Tan is Positive, and Grey is Negative
Passenger Side: Light Green is Positive, and Dark Green is Negative
I soldered 1 foot of wire to my speakers. I cut the old tweeter and speaker wires and soldered a foot of wire to the two wires that were going to the old speaker. I then taped and hung the wires out to the side where the tweeter was when I put the new speaker in. Gave me more than enough wire to run to my crossover.
The crossover was a concern for mounting. I wanted it between the door and the panel, not inside the door, to avoid moisture damage. Since not running an amp or anything, people on the car audio forum I posted on all said that there should be little to no heat. So... and hopefully I made a good choice... I poked two holes in the padding and zip tied the crossover over top of the window motor access hole. That way when the panel is put on, it'll have enough room to push back into and will hold in place with no rattling.
The tweeters I put into the door panel, right near the black plastic that covers the bolts for removing the side mirror. Tonnes of space behind it. The tweeters I have were flush mount, sat about 3/4" in, plus there was a bracket and a bolt which extended another 1.5". I thought I'd have to cut some of the bolt off, but fit in without any problems.
To cut the holes, I ended up using an Olfa Circle Cutter... very clean hole, no centre hole needed drilled. I can glue back what I cut out and I'll bet unless pointed at, no one would even know it was cut out.
Sadly, despite checking 3x, the driver side door hole was off by just under 1/8" which brought it a bit too close to the edge of the door. Still, looks good, almost factory. Just a 'bit' of gaps under 2 sides because of the contours, but the gaps are small, can't even slide a dime under them.
Not really a step-by-step... but hopefully helps a few people. If doesn't 'pass the mustard' as a DIY, please move to general 7th Gen. Thanks.