Jay916

Im trying to retain my stock 4.3s head unit and hook up my door speakers to an aftermarket amplifier, can someone help. I dont know if there is a stock amplifier or not. I already have a line out converter for my 12's (shop did it) but im trying to save some money and do it myself. I got the speakers and amp for the doors just need to know which wires to splice into. To run the wires. Door speakers have a plug on sidewall so kinda hard to go through there. Any info would be nice.