both the 2.5" piping and larger intercoolers have this result:
What you are overlooking is the fact that although there is more volume, that will only account for 65 milliseconds of additional lag at that flowrate (this was calculated about a year ago when I began this pursuit and documented on this site), but, the benefit from less restriction to flow and an intercooler core that is more efficient is benefiting power production across the board, spoolup included.