Chassis ground vs cable ground..
 

interesting video highlighting the difference in voltage drop when using chassis ground or cable ground..



http://www.youtube.com/watch?v=_Bpdh2BD-qI

This is why I've never run a ground. I run from my amp grounds to a block and from the block to a nearby unpainted ground point.

I just ran a ground to the trans from my trunk mounted battery. You can tell the starter spins faster.



Left all the factory grounds where they were. The major ground from the trunk battery is to a set belt anchor bolt and a ground buss mounted on the inside trunk wall. So I added a 6 ga wire from the ground buss to the factory trans ground point.