I have a Jl Audio 8” powered subwoofer for sale. I DO NOT have the wiring harness, but you can get one from Crutchfield pretty easily. It’s a ported subwoofer box with a built in amplifier that is rated at 250w rms. Online this exact setup is selling for over $600, all you need is the wiring harness and you have a sweet sounding subwoofer in your ride for a pittance.