I honestly don't know. If the thing sucks nothing but hot air under the hood, then the loss would be more than that, and I wouldn't be surprised if it equaled the stock airbox. If one were to open the flap next to the radiator for cold air, just like when installing a Volant, then fabricate a small 2" high block off plate for the rear of the filter (it only comes with an inside block-off panel, facing towards the engine), it would flow just as well as with the hood open.
I have to say that I was not only impressed by the K&N filter size (it has 60 - 5.5" wide pleats, compared to 54 - 4.375" wide pleats on the Volant, and 24 - 5.5" wide pleats for the AirHog), but the velocity stack shaped intake transition from the huge filter to the MAF was very nice. It also includes a hard intake tube to replace the stock accordian rubber one. It's a very nice setup, just loud. I looked into adapting it into the Volant and a modified (gutted) stock airbox. There is just no way to fit that big filter in there. The MAF adapter is also too large for the filter with the Volant.
K&N only misses the boat in not enclosing their FIPK in an airbox for noise. Most people get sick of the noise after a short while, and remove them.