Factory Amp Pre-out?
 

Does the factory 6 speaker system have an amplifier output? (was thinking of an easy way to add a subwoofer).

no

youll have to use high outputs :) to use the stock system with an amp sub
phil

The headunit has preouts for an amp right?

no, use will have to use speaker-level inputs to an amp.

preamp (RCA) outputs give a better sound, but unless you replace the factory head, you'll have to "tap" off of the speaker wires.