The amount of current draw depends on how much of the amp's power you will be using. Just because it says 1000 watts does not mean that it automatically draws a certain amount of power. If you fully use the potential of both of the amps I would say the 4g is just about being maxed out. Can't remember what the max current 4g cable with a length of roughly 15ft can handle. Should be around 100 amps. Whatever the current draw is, that is the max size fuse you can use in the 4g wire. There is a major misunderstanding of what the fuse by the battery is for. It is SOLEY there to protect the wire, nothing more. Once the 4g is in the trunk get a distrobution block and feed both the amps. I would put the cap as close to the sub amp as possible. That is where the headlight dimming stems from. But most important of all is the ground. Make sure the ground is at least the same gauge as the power wire. And be sure all ground connections are mint.
