I started the first phase of my install yesterday. This was the install of the Pioneer AVH-W4500NEX and the GM-D8704. I had a local install guy help with the install. He is mobile and I could not take my car to drop off for a day.
The install went OK. He ran into a few issues. The main ones being the shipment of wrong products not caught until install was pretty deep in. If anyone has any suggestions on how to diagnose #1-#3 on my own as a DIYer, that would be tremendously helpful.
Issue #1: The mechanical, foot emergency brake stopped working. This could be coincidence, but it happened immediately after the install.
Issue #2: The console USB port is not working.
Edit: Partially corrected. The USB port works with a thumb drive. When connecting my Galaxy Note 9, the cable is not always making a connection to the phone. When it does make a connection, the 4500NEX states "Incompatible USB Device". I am starting to research that part of the issue now.
Issue #3: The phone buttons on the steering wheel are not working. I did verify that these are on the Wallet Card from the Maestro RR flash.
Issue #4: This was an issue with the 4-channel RCA shipped. It was suppose to be 17 feet, but they shipped a 12 foot cable. It was not realized until after all the cable runs were complete and he was about 3 feet short to the amp. He had to use butt-connectors and a 6-foot RCA cable to get the connected. Not the best solution, but the only option available. Unfortunately, I may just live with it because I don't want to have to re-run the entire cabling myself.
Outside of these issues, the sound is incredible compared to the stock head unit. No tuning or anything has been done, but the volume can get to where I like it, the sound coming out is much clearer. I have quite a bit of learning to do with Android Auto and some of the other features. I am guessing part of this has to do with the USB not working.