Backpressure loss w/ I/H/E?

[kenis138]

Sine I did I/H/E setup, noticed that system seems to be missing some backpressure. For example, when let foot off throttle, revs drop like a stone. When downshifting (if no revmatch), not nearly as jerky. Can anyone explain this phenomenon to me? I know there must be some backpressure loss expected b/c yer freeing up the airflow, but how much is too much?

[CleanBlackSi02]

You sacrifice torque in the midrange by not using the stock airbox. However you have more top end now...maybe that's what you're feeling?