[millsp]

if you have the NON JBL system in your vehicle now you will need to add a center-channel speaker for that AMP. The NON JBL system does not have a center channel speaker just an empty hole. As for wiring harness you can get a standard Toyota wiring harness to plug in behind the head-unit to use the factory wiring for the speakers. If your using the factory speakers you will be fine, you will be disappointed with the audio quality and will eventually want new speakers thus you should also run quality speaker wire to each speaker.