Guys. STFU about the ground. 0 gauge wire is no worse of a conductor than the thin (and not copper!) metal of the car body, which, guess what, ALSO HAS RESISTANCE.
Throw a pi filter on the power input to the HU. Cap to ground, choke in series, cap to ground, then to HU.
Throw a pi filter on the power input to the HU. Cap to ground, choke in series, cap to ground, then to HU.
