Originally Posted by ChrisSlicks

You can do a rolling dyno of sorts, not to measure HP but to measure acceleration. Requires an accelerometer setup. It would be pointless without a baseline setup though, and ideally baseline and installed should be run on the same day under same conditions with some driving miles in between for ECU learning.

Yes at speed there will be more air coming in but exactly how much we really don't know. That debate has already been brewing about the Stillen G3 after 370Z magazine had poor dyno results with it.