My theory on the manifold is to optimize what is there. Keep the long runners for the low end, but extrude hone the runners for more flow and move the obstruction to the intake air entering the runners by spacing the plate away from the intakes. I see the shrouding of the entrance to the runners as the main impediment to flow. I may be wrong, but I think the point is valid. Some heat resistant coatings would be good to keep the intake charge cooler as the manifold is a large aluminum heat sink.