I have my amps (all three) sitting on 3/4" MDF as part of the fiberglass amp/sub enclosure in my boot. Found that I needed really, really beefy grounds. Also, I made a sandwich of vinyl and aluminum (thick aluminum covered by thick vinyl on each side) that is between the bottom of the amps and the top of the MDF mounting board. This also helped. I'd say that it's still *barely* there. Due to the battery being under the boot floor, the only way to truly get around this would be to raise the amp up.
R
