The easy way is to just run speaker wire from the amp to the back of the radio... connected to the vehicle side of the radio harness (NOT the radio side). This way if you ever decide to revert back its easy to do. Unless you are going full competition status, you will never hear a difference in quality. The only time I've ever fully rewired a car was for 2 competition vehicles and one really old car where the factory wiring just crumbled in your hand. Otherwise it was always to the back of the radio. Make sure to run power wires and signal wires on opposite sides of the car. And use a factory bolt with all paint sanded off for your grounds.