Audio Systems: Theory I came up with and need some answers, chevy silverado, factory radio

Question
I have a 2009 Chevy Silverado and I really don't want to put a new stereo unit in just for a sub.  Then I had this idea, use the 12V lighter port and auxiliary port to power a small sub.  My truck has 2 of those ports right beneath the stereo unit.  Is it possible to use both of those using a converter/inverter to change the power to go to a small say... 200-300w amp ounted to the box for the sub and have a small sub like 4" or 6" and not have it bolted in.  Then for the audio signal, instead of pluging an aux cord straight from a phone to the port, some sort of preport thing that would plug into the aux port and then the aux cord would plug into it and the bass line would be picked up and sent to the sub and then send on the rest(treb/mid) on to the trucks stereo.  Is there a way for this to work an if so, could I possibly get a recommendation to where to get the help to make it? Thanks

Answer
No sorry bad idea, the cigarrete lighter port its a low current output for cellphones gps  or a lighter, also the wiring is not capable of sending the current any amplifier will need,
you have to run a battery power cable  
and a hi low interface for your factory radio

http://www.oemautosound.com/p-271-add-an-amplifier-to-your-gm-radio-2007-2012-ao