Making progress on the sub box. Should have it covered by this weekend. Still trying to figure out the grill cover. I also wired in a GBCM (generator battery control module) that controls the alternator output. Before the alternator was just defaulting to 13.7 V (13.1 on the gauge). Now it will vary the voltage based on demand, battery state, driving conditions etc. It's a pretty "smart" little module. Here's a good write-up on it if you are interested:
http://www.silveradosierra.com/resources/file/529961
https://www.motor.com/magazine-summa...september2015/
https://www.motor.com/magazine-summa...september2015/