Chris
checkout Lynn Hanover's excellent treatise on flow testing in the archives
posts #41010, #41011 give a simple flow bench to test restrictions
remember even an open pipe is a restriction over free air, the longer or smaller the pipe the more the restriction, so everything prior to the rotor is a restriction. smooth walled pipes are better than flexible pipes. an intercooler is a necessary evil in a turbo installation, adds restriction but better than the added temp.

Andrew