its actually better to go to the bat neg, B i think it was said he noticed a big difference when running a dedicated ground from his bat neg, but the way Da Wa said is more practical and is what most ppl do, b/c amp kits usually come with only 3 ft ground cable and u dont have to buy another run of wire to go to the battery, but ive heard of ppl using the seat belt but ive never done that i just find a spot in the trunk(which there may be a ground bolt in your trunk from the factory, like there was under the carpet in my probe) or you can jsut scrape off the paint to expose the bare metal on a spot under your carpet in your trunk which will also work good for a ground spot...
if your batt is your trunk, i would do it like that. but if you only have one batt in the front, thats a bad idea. amps only come with 3 ft of ground, because your ground is not supposed to ever get longer than that. the longer the wire, the worse the ground gets, and having a good ground is one of the most important things.
I've seen conflicting tests, but to me, the consensus is the chassis of an average car will be less restrictive than a run of 1/0 wire to the batt - maybe 2. If you're running several thousand watts and need the current capacity of multiple strands of 1/0 then run them to the battery. Otherwise the chassis is the best option.
I have my ground on the bolt that you were talking about, but the other day it got knocked off... I put another terminal on it and mounted it back in the same spot and now there is alternator noise and a loud thumping noise coming from my amp. I've tried almost everything. I cleaned the area, I regrounded it on another ground bolt. I can't seem to find what I'm doing wrong. I'll try the seat belt thing, but How do you get it to stick?