New fit owner :)
 

i just purchased my fit last week and am installing all new door speakers and 2 12" subs in the back , i am keeping the factory radio though . So I am goin to run a line converter off the back channels . So my question is where is the easiest place to tap into the wires closest to the rear of the car ? i was not sure if it would be best to take off the panel between the front and back doors and access it there ? cuz i know there is a side airbag there .

I always tap in behind the radio. It gives you easy access to all four wires and if you ever change your mind the RCA's are all right there.