I have a 2009 F150 STX Extended Cab and would like to know if the factory head unit is capable of having an Amp hooked up to it. I am looking to upgrade the sound system and havent decided on a head unit yet but have an amp and subwoofer in mind as well as replacing the front and rear door speakers. So I was wondering if I can replace/install all this with the factory head unit until I can make a decision on which one I want. Any suggestions on speakers/head units would be greatly appreciated and thanks for the help and suggestions