My take on all this is that a properly designed and constructed copper radiator will put cool an aluminum equivalent. Same should also apply to intercoolers as well.
Obviously if it's built or designed poorly it's not gonna work well. But given an otherwise equivalent aluminum or copper unit the copper one will have a substantial amount of extra thermal capacity.
The difference is the copper will weigh more/have more rows to cool the same as aluminum. I would never buy into the triple pass stuff, the longer the water sits in the radiator the longer it sits in the block, at low rpm that is a no go.
