Brake Controller (Adapter Link) installed today.
I also ordered a sub box, just need to get the Maestro RR (w/GM3), Dash Kit, GM Antenna Adapter and wiring harness and I can install the stereo.
Found Rear AC Vent Deflectors, wondering how much they actually help.
Looking at getting a Power Tailgate lock, and 2.5" lift/leveling kit, in the next month or so, and other misc. little things.