I know this has been discussed before, but I am still unclear about a few things. I have a four gauge wire running from the battery which connects to my distribution block. However, my distribution block "T's" off into much smaller connections for the amps. The connections only allow for 8 gauge. The amps I am running right now are much smaller, so the 8 gauge is fine. However, I plan to upgrade to JL Audio 1000/1 and 450/4 or equivalent. So my questions are

1. Do I need to run a thicker gauge wire from the battery or is 4 gauge sufficient?
2. Do I need to run 4 gauge power wires from my distribution block to each of these type of amps?
3. How about the ground wire? Do these need to be 4 gauge also to the distribution block and to each amp?

Thanks for the help.