At what point is the airbox no good when you using a turbo on my gen 1 busa. I see a lot of air pendulums made out of metal for turbo applications. Is this because of the heat from the turbo going through the airbox or is this just help prevent leaks? I'm starting to do my first turbo build and I've taken the motor out and ported the heads and now just looking at all the other things I need to upgrade while I have the engine apart.