Read the descriptions VERY carefully of the knuconcepts stuff. Tinned wire and aluminum aire are not as good condictors as pure copper so it's generally best to go 1 size up.

Also their distribution blocks and fuse holders have a cheap black plating on it that adds a lot of resistance and can build up enough heat to melt the plastic of the fuse holders.

 

really? I havnt had any issues with my distros from them so far and i have 0ga running through my car and there 0ga CCA for the big 3 :S guess it must take a while since ive only had them on for like 6months, but for the price there stuff is good IMO and i believe they do have multi amp kits: 0ga dual amp kit is here 0 GAUGE DUAL AMP POWER KIT

and here is the 4ga but it doesnt have distros 4 Gauge Amplifier Installation Kit

 

Thanks ChristianM, that 4 gauge kit looks lke it's exactly what I need.

Sikk Nation, now I'm confused cause I looked into what you said to read carefully and it says that the power wire is tinned but is also pure oxygen free copper wire so I dunno what's going on there.