So I successfully relocated my battery, keeping the ground in the engine the same place, bolted up. I added another ground inside the spare tire area by sanding down the paint to bare metal. the positive goes from the battery, to a circuit breaker, then inside the car to mate with the stock distribution block. I've had it like this for about 4 months with no problems but I guess ever since the weather started warming up, I can hear my rpms through my rear subwoofer. Any ideas what would have caused this all of a sudden? A friend told me to run the ground wire all the way through the bottom of the car and attach it to the distribution block instead of having two grounds, would this help in any way? Thanks.

 

I would recheck your current grounds to see if they had come loose/corroded. AFAIK You cant have too many grounds.