I haven't done the math but the easiest way to see if you've got a restriction is to simply plumb a mechanical vac gauge behind the filter, go WOT, and see how much vac you pull. You will likely pull some but shouldn't be pulling a bunch (like stock intake pipes). You could try pulling the filters and doing the same thing to see if the filters are to blame too but I'd do that on a dyno vs the street.

 

That is a pretty cool idea actually.