What evidence do you have to back up your claims? It seems to me that there is a limited amount of space in the engine bay of the Z32 to put TT manifolds. Thus, any manifolds are naturally going to be similar in design.
I'm not saying you aren't right. But just saying so doesn't make it so. It seems to me everyone is quick to say they're copies, but no one is providing any real proof. The closest anyone has come, actually points to them being different.