To be honest iv seen many many high end installs done with CCA.. Amperage rating is only 50 amps different between CCA and OFC. I know that Sky High Audio's Truck uses all CCA for sure, along with many other big ground pounder builds.

Amperage rating is one thing (thermal capacity before wire heats up and melts). Copper is more conductive than aluminum therefore due to easier electron travel you will have a greater voltage difference. A higher voltage at the amp(14.4v vs 12v) means your amp will efficiently make its power with less current, straining the alternator as much.

I'm gonna defend CCA. I've used it in 4 builds so far and no trouble. For someone on a budget and not going extreme I recommend it. Now I do own OFC and plan to run that later on a more serious build. OFC is for sure better. But I can't seem to believe cca is useless.

^^  You are making a subjective assessment, and it is useless. 

Additionally, you can never correlate overall physical diameter to actual gauge.  This is another reason people have no idea what they are talking about when they compare wire.

 

CCA is a marketing gimmick.  If you are running it, you fell for it.  Plain and simple.

I went to my local welding shop today and seen there 4 gauge wire .. its not as thick as the cca wire I have now.. but since its ofc.I'm guessing it makes up for it?

The overall thickness has nothing to do with the amount of conductor cross-sectional area (Awg).