I recently bought a 5.9 ZJ that the previous own pulled his amps and subwoofer.
Had to put a new amp and 10" subwoofer in it, sure sounds good now!!!
I had a shop do the work, they didn't charge for labor as the wiring was already there.
Here's a before and after of what it looked like under the back seat.

amp_wire.jpgamp_wire2.jpgamp_wire3.jpgamp1.jpg