Can I add a subwoofer to the factory system?
Yes. To add an amp to the factory stuff you can do it a couple of ways. The first is to by an OEM-1 made by PAC. Its plug and play with no splicing of the wires at all. It gives you a set of RCA (2 if you want) and a remote turn on. The second way is basically an OEM-1 but involves you putting a few wires together yourself. Still dont have to cut any factory wires though. You will need a line level adaptor. I recommend an PAC SNI35. Then you'll need 2 radio wiring harnesses. A Metra 70-1858 and a Metra 71-1858. Take the 2 wiring harnesses and wire them together, color for color. You'll end up with a harness that plugs into the cars radio harness on one end and plugs into the factory radio on the other end. The blue wire in the harness will be your true remote turn on. Then take your line level adaptor and wire it into the speaker wires on the harness you just made. If you tap off the front speaker output the colors will once again match up. Now you have a harness that allows your radio to work exactly the same as before but with a set of rca outputs and a remote turn on. Both ways are essentially the same thing, just that PAC has made it slighty easier. The second way can be found using parts that you can buy at just about any car stereo store but requires maybe 10 extra minutes of work on the bench wiring it. Either way the price will range between 50-60 dollars. Another option is just to splice the line level adaptor directly in to the cars radio harness. Perfectly fine but I dont like having to touch the factory wiring if I dont have to but its cheaper as you are only paying for the price of the adaptor and not all of the extra harnesses. You would hook the input leads of the line level convertor to the front or rear speaker out puts of the radio.