angrylittleman 
Here is the Key...
... Replace your OEM head unit.Originally posted by tomcat837
I will like to know how to add an amp to the factory speakers...
Thank you
Just about any aftermarket head unit provides more than enough power to max out the factory speakers. Most new headunits average 25watts per channel RMS and can pump out 200 watts peak, heck most will force you to replace the factory speakers in no time flat. Get an aftermarket head unit with MP3 and/or WMA capability and you will not need the changer. Also make sure your new head unit comes with Subwoofer outputs and all you need is a class D 1 channel amp for your sub (or a 2 channel amp bridged). In any event the best way to go is get rid of the OEM equipment.
The factory speakers are basically matched to the OEM equiment. Running speakers above their RMS rating is not a good idea, but some people still do it with mixed results. 18watts MAX on the stocks and I believe only 4watts RMS.
