Girlbear , staying up all night? me too , working though. In my experience factory speakers range from 6 to 10 ohms depending on make , model and speaker size . Polarity of the wires is difficult to figure out .You probably already know what the aftermarket ones are since they are all 4 ohm for automotive . Your factory unit will sound louder because factory radios are designed for the higher resistance Although they are not rated on output wattage , most factory radios are more powerfull than most aftermarket units . Its the fancy bells and whistles the aftermarket units hook us with . Rob