Hey Douggie !
Sorry, I didn't mean to change the thread.
We run 2" K & N on the sprint car with no cfm depletion problems but, it's always at top rpm when the injectors (or carb in this case) are fully open and sucking in a lot of air, not at idle or street cruising. I'm sure with a clean filter, you wouldn't have an issue. That would be a nice comparison test on the dyno.