I have an '04 Sport with the stock 6 speaker stereo system. Does this setup utilize power from the head unit or does it have a separate amp. IE can I use the stock speaker wire or will I have to re-wire when I replace the head unit and speakers?
On my 2002 4runner, behind the headunit is a small amp to power six speakers. It's rather small and attaches to the headunit, but it is a separate unit. I assume that your system should be similar.
Yes you can use the stock speaker wire and everything with the stock system. With the JBL system (like mine), the link to the amp in the rear is all digital - so I would not be able to do that.