is it possible to install a sub using my stock unit? sorry if it's a dumb question....total noob to car audio. If there's already a thread about this just link and delete. Thanks in advance

 

Yes, you can buy a converter.

 

Line Out Converter is your best bet. Just did this to my friends Acura TL.

 

have it on my fit but i would get a new headunit, sound quality is much better for the stock speakers with a little extra watts, thats apart of my tax money is a dvd player

 

I would only use the Line Out Converter as your LAST resort. My friend already had a stock navi system thats why he didn't want to replace the whole head unit. Definitely go with an after market head unit that has the amp out, way better sound quality.