The ccv mod is a redirection of the hose that recirculates the crankcase vapors back into your intercooler. Many people run a hose into the exhaust and let the vapors blow out through there or just run a hose down and out to the side. The vapors will fill your intercooler tubes with an oily residue that traps heat.
I don't know if the 6.0 needs the crossover or not but it is designed to create a more even oil pressure between the two heads. I have it on my 7.3 but do not know enough about the 6.0 to tell you if you should do it.