How did you gain your amp? Maxed out? How is your ground looking? Did you find a good place to ground and did you grind the paint off the area? Also is your RCA's ran by power wire?
You have 8 gauge throughout but have a 4 gauge ground?
Its my first audio system! I have an 8 gauge power wire and a 4 gauge ground...call me a noob if you want lol
Found your problem, like sucking a golf ball through a straw.
I was having a popping issue with my kenwood Hu, changing track, POP. Loud turn on pop. Did the pioneer trick of grounding the RCA's and the issue is GONE!
If you have not a clue on how to set the gains and such and you maxed stuff out, your voltage is dropping like a lead balloon causing your amp to get hot and your subs.