Well I tackled the rear doors today. Easy to get the panels off with the big fork like trim tool removal tool I bought.
The hardest part was running new speaker wire through the rubber accordion conduit that links the chassis with the door. I sprayed WD-40 into the conduit and also sprayed the wire and it slid through. I ran 14-gauge speaker wire. The stock wire is 18-gauge hence why I ran new wire.
I didn't need any brackets for the Alpine SPS-610 speakers I installed. All I had to do was drill new mounting holes. I used anti-vibration tape between the speaker and the door.
So all my speakers are now installed. Alpine SPR-50C in the front doors, Alpine SPS-610 in the rear doors. All hooked up to an Alpine MRP-F300 4 channel amp. Very very happy so far.
All I need now is a JL Audio Stealthbox sub. That's going to have to wait though as it's crazy expensive.
I took some pics. Left rear door, right rear door and the Alpine amp under the front passenger seat.