My Riviera was the same way. I had 2 infinity amps, Avic D3, kappa components, kappa 6x9's, and Infinity Kappa Perfect Sub, and all the alternator whine in the world, i couldnt figure it out until i realized for some reason the power wire from the factory harness had alot of interferance, so i ran a new power from the ignition wire and a new ground right to the body of the car. It worked well, no distortion.