Ground Chassis v. Ground Neg Bat Terminal

what are the cons to supplying a ground for your eqiupment directly from the negative terminal of the battery? is the potential for inducing more noise into the system greater? versus a clean ground to the chassis?

i know the length of cable will always be less for grounds to the chassis, as runs to the negative battery terminal would be lengthy from anywhere within the car, especially for those items mounted in the trunk, however, i think of the car chassis as one large negative battery terminal. should i not think of it as this, and remember that a shorter ground length is of the utmost importance as long as termination of the ground point is secure and solid to chassis metal?

for the first time in an install of my own, i have developed alternator whine, and it is extremely discouraging -system sounds great when car isn't running, but as soon as ignition is turned on, horrible whine with variation in engine speed is present, and unbearable.

to amp- fused 8 gauge to positive terminal, 8 gauge to negative terminal, rca's from hu to amp, remote lead fead from acc+ in wiring harness.

i have read countless past posts here through search and most will find this post redundant, but it seems alternator whine is luck of the draw.

any opinions? thanks, Brian

yes, rca's are on opposite sides and, no, the amp, is on the vinyl material underneath the seat, not metal.

hey, as long as i don't 'drive' the car, everything sounds beautiful!