Well, the 83A is if your car isnt running. Its only 71A while its running. But you're pulling around 143A when its really thumping. If its dimming at low volume, you need to test your amps ground wire. Where is the ground mounted? And I hope you're not running an 8 gauge wire. An 8 gauge wire cant support that kind of power. You should be at least at a 2awg wire.