Alright, I'm looking to upgrade my deck so I can use my phone to stream music using Bluetooth. I get a good discount where I work and am looking at This to install. My question is that I have Premium sound from the factory with components in the front doors and a sub under the passenger seat. Looking at the harness for the factory sub it looks like it is wired into a set of speakers and may have an internal low pass filter.

I need to know what the factory sub is hooked to and if I should use the line sub output on the JVC deck or if it requires a powered output from the speakers like I believe it is.

Please help, thanks in advance.