How to add a amp and sub to stock radio?

Can anyone tell be what i need to install a sub and amp to my stock radio?

 

If you get an amp with speaker level inputs you can tap into the rear speaker wires. Or you can buy a line out converter that hooks into the rear speaker wires and provides a set of rca outputs. And of course a power source for the amp itself.

 

If price isn't an issue you could have an authorized JL Audio dealer put a Cleansweep in it for you. This levels out/cleans out any distortion out of your factory radio so it will make your factory speakers sound better and give you the option to add an amp for a subwoofer(s). Also you can hook your Ipod up to it.