This might sound like a newb question but i am one , here is my question ,I currently own a 91 Maxima GXe and will be replacing the factory speakers soon and want to run a 200w 2ch amp to power the speakers, now my car has a factory amp in the rear deck and it has the wires, here is a chart (none bose chart) but but I want to know is can I just extend the amp wires and connect it to the aftermarket amp or would I need to run new wires from the oem harness to the amp and also what about the rca cable would I still need to connect them, if so I guess I would need to get some y adapters so I could connect the rca cables to my speaker amp and sub amp

 

Two basic methods to connect amp/head unit/speakers.

1) LOW LEVEL inputs. These are the RCA plugs like all your audio video gear at home use (or used to before HDMI). Your head unit would hopefully have female connectors on the back called PREOUTS. One, two, or three sets. SInce you are using a factory head unit, magic 8-ball says "doubtful". Then you plug a double male RCA PATCH CORD from the head unit to your new amp. That takes care of getting the signal to your amp.
Next you simply wire up the speakers to the speaker connectors on your new amp.

2) HIGH LEVEL INPUTS is fancy *** wording for tapping into the speaker wires themselves if you do not have RCA PREUT JACKS on your head unit.This way you can still use an aftermarket amplifier with a cheesy factory head unit. Some drawbacks though.

If you do a search on high and low level inputs, you will get more answers.

Hope I answered the question you were actually asking