I have all my speakers replaced, and the only factory wire I used was what goes from the door to the inside of the car, I cut the speaker wire about 1ft after it enters the car and ran my own wire to the amp in the back. the reason was because trying to run my own wire into the door jam area is a PITA! but I did this in my sister in laws silverado chevy truck and it was real easy because its a big vehicle.