Thanks for the very helpful procedures on adding an AUX in / mp3 jack to the Xterra stock radio. I decided that I liked the idea, but was not skilled enough to solder to the points that you chose. I asked a friend for help and found alternative soldering points that are much easier to solder to and it worked! The sound is awesome. There is no quiet sound problem like I've read mentioned in other posts/forums. I can crank it way up. Louder than I need. It's a 2004 Xterra. Here are some photos of what I did.

This one shows the general location of where I soldered to. This is the CD changer board. Sorry that I don't have pictures on how I disassembled it to this point, but others have posted detailed disassembly photos.

This one is zoomed in and shows the details of the soldering points:


Here's another zoomed out general location:

Here is one showing things more assembled back together and the wires hanging out the back:

Here are the wires hanging out the front:

Here is after soldering the wires to the aux in / mp3 jack:

Here is where I installed the aux in / mp3 jack on the console. It doesn't show it, but I added a bunch of hot glue gun glue to the back of the console that is shown in this picture. This made the jack feel much more solid and I highly recommend:


So with this post I hope I'm helping someone else out as much as you helped me out. Long live the internet and the free sharing of ideas!