need some low range in my 97 BD

[97 legacy sedan with an 03 wrx head unit]

hokay so i just replaced my rear speakers cuz they were blown to little pieces with some cheap pioneers. they dont have much lower range and so im wondering if i were to wire a sub in what are my options and how should it be done.

1) is there an oem sub that comes with newer model subies that will plug right in to my car/head unit?

if not how are cheap aftermarket subs wired?

do you just hook up the amp to a 12 volt then get the audio lines from the rear speakers or do you have to run a line from the head unit.

-im guessing that if its possible to just run a line from the rear speakers i will need a converter box to convert to component for input into the amp...

- is there a sub hookup on the stock 03 wrx head unit?

any idea what the cost of this project will be? - with a basic BASIC sub. like 10 inches with no fancy bells or whistles.

Thanks

The aftermarket subs work pretty well. I have an infinity basslink that I have used in another car and it sounded really good. You just have to turn the bass on your speakers down and let the sub do the low range - otherwise you can get a lot of distortion. If your HU has preamp outs for a sub, then it is best to run the signal all the way to the HU. If not, you can tap the signal off your speakers. You also want to run the power all the way to the battery and there will be a switch wire that you hook up too. I also installed a switch under the dash on the switch wire so I could toggle the sub on or off if I wanted - useful during talk radio or sports broadcasts.

Actually, I was about to put this basslink on ebay, if you are interested.