That's what I needed to know (BOOM). I knew there was something there just never thought of the gas tank until now and it makes sense. Guess the subs are going in the rear. So if I replace the front speakers with some, say, infinity kappas or something would it be better to run them off the deck power with x-over box (included) or off the factory amp (x-over box or no box?) and then just use my deck pre-out to run a mono-amp and subs in the rear?

OR

A 4chan amp to run the fronts and subs and leave the factory stuff alone?