Do they make a dist. block that is 4awg in and splits it to (2) 4awg out? I've been looking but I cant find one. Right now I have a 600 rms amp just hooked up by itself to my subs and I wanted to add a 4 or 2 channel amp and look into some better speakers. Then I was just gonna run each amp on a 4awg wire. Would I need to upgrade my in line fuse also? Thanks