Hello, new here. I own a 2012 FX4 SC w/sony premium sound and GPS. Just curious if the sub signal runs off the 4 channels or is there a 5th channel for it? JL offers (for another $100) another add on to flatten out the sub output. Has anyone installed this with the same factory options I have? I just can't stand the sony system anymore. I have a complete JL system in my older F150 and that's the only thing my newer truck is missing to make it perfect. This will be a lot more work to wire everything up, the door panels look easy but fishing for wires in the dash looks intimidating, but so did my old truck in the beginning.