biggest fkin motor you can fit +biggest fkin turbo you can fit = bigest fkin intercooler you can fit ???
sound fair enough ?
there is one rule that says the core volume should be 1.5 times times the engine capacity
or i can find you the formula that will work out exactly what the size the core should be for your HP but you need to know your airflow , how efficient your turbo is , what the ambient air temp is , and so on .