In other words, changing the in/out flanges from 2" to 2.5" won't solve the issue of whether the cores can flow the extra volume of air that 2.5" inlets/outlets afford. So, say I have a nice set of Stillen SMICs, are the cores now a bottleneck after I've solved the 2" flange restriction issue ? The same for the plenum...if you open the throttle body opening, do the intake runners limit the flow. Seems like I'm chasing the bottleneck from one place to the next.