Steve, please consult with Holley but I'm quite sure they will tell you, the hoses from the eight runners must all terminate in a common plenum. This is to absorb the pulses from individual cylinders. A MAP sensor doesn't work properly if the signal pulses. Rubber hose alone won't be enough. An IR intake is a very different animal from a single plenum type of intake. How large that plenum needs to be is a topic of debate. You saw the size of mine. The IPSCO one is 3 x the size. The one Borla casts into the base of their manifolds is 10 x the size but you can run MAP and IAC in the same plenum. Here's a photo of an Inglese plenum on a Hall Pantera manifold. I'm also told, the hoses from the port to the plenum should be as short as possible, so a remote plenum isn't a good idea. The theory is, you want the vacuum signal reaching the MAP sensor to be responsive yet pulse free. I know; sounds impossible! Oh, and the hoses should be the same length. Prior to my Holley Dominator ECU, I had an Accel Gen 7 and Accel told me I needed a plenum with a one liter capacity. I ignored that recommendation but it appears Inglese did not!
