Verified answer

If you only want the bass go to your loca sound shop and ask for a universal adaptor for bass "dont really remember name" Which is less then buying aftermarket things.! It plugs into your factory radio speaker wires,4 wires total. You'll need an amp the standard connection and bass speaker. It looks like a black box with four wires sticking out of it and RCA plugs into it .

You can, but I wouldn't for a couple reasons. First, it's a pain in the *** to wire, as stock radios generally don't have preamp outputs, which will run to your amp. Secondly, factory radios put out very little power, which generally results in the sub overpowering and drowning out your speakers. If you're gonna do it, do it right. If you wanna do it right, replace the whole system. Aftermarket head units have better sound processing and preamp outputs. Aftermarket speakers aren't made out of paper, have larger magnets, and rubber surrounds instead of foam. External amplifiers will provide far more and cleaner power than your paltry factory head unit. Spend a good $2,000 and do it right.

If you've logic7 audio, you'll need a special made adapter that's going to be plug and play to your amp and sub.