Do you have a battery in the rear that's near the amplifier? If so, I would just ground to that, and the battery is grounded to the frame. If your talking about running a ground wire from your negative terminal on your starting battery ALL the way to the back to the amp, that's just a waste. (assuming your car has decent grounding points in the engine bay, which it should) No battery in the back. And yes, I was talking about running it all the way to the front. I'll also be doing the big 3. Then I wouldn't bother, traditional positive power line and grounding cable to frame (short as possible) will work fine. Look for the grounding wires from the engine to the frame, they may be exposed braided steel wire. Just add additional wire at those points. Add another cable from chassis to negative battery terminal. Then lastly, cable from output stud on alternator to positive terminal on battery (fused). <--When you do this one, make sure you have the negative battery terminal disconnected. Hope that helps. I am that big of a noob, lol. Thanks for being helpful tho.