I have a question about these big bore kits? Do you need to utilize a rotax airbox that brings in cool air to make max power?

Also, for us guys that are still running the 912ul, does anyone know if we would see a horsepower increase like the 912ULS does of 5 hp when adding the airbox? I always thought it would stand to reason that the 912ul would benefit from that, but never found people as knowledgable as what I see on this thread to ask. So what do you think?

Paul