Who gives a **** if it's all copper or cca. You'd be better off buying double runs of cca than a single run of copper1/0 for the same price.
Unless you are competing and for some reason really need copper, just get the cca. It'll be fine. Cca 1/0 will be larger than copper 1/0 to compensate for it's lesser conductivity if it was designed properly by a decent company (like knu, monster, etc...)
If you really think there's going to be a difference in cca vs copper (considering both designed well from a reputable company like knu...) in a 3 ft run, you're an idiot.
Save your money and just get the monster 1/0 that's cheap right now or the cca knu.