I currently have the same powered subwoofer mounted under my driver's seat. I bought the
Kicker RCA adapter and a
Toyota wiring harness adapter. This makes it a little easier to hook up and you won't have to splice into any wires in your factory harness.
I also mounted the remote bass controller into that small compartment in the center console. I'd still like to swap out some of the other speakers but so far I'm pretty happy with the sound after adding the Kicker subwoofer.