So I am looking to buy a new HU, amp, and sub soon and was wondering what each person preferred. Looking for a single din setup with between 500-1000 watt rms subwoofer/dedicated amp combo. I am planning to set this up behind the back seats in a 2011 double cab with the JBL system. Loss of storage isn't a problem. Also, I heard that a new HU is needed to upgrade the subwoofer on the JBL systems, is this true? Feel free to ask any questions, too.
P.S. Please include anything else I might need to power a system like this, new battery/Big 3, etc.