Look at the size of the pannel filter. The huge size of the filter is plenty to feed that throttle body. The midpipe and throttle bodyare about three inches, the panel filter is much larger than this. If you made a short ram intake with the large panel filter as the mouth it would draw in plenty of air to feed the 3inch midpipe, the filter is about five times bigger than the midpipe it would feed
This is my plan, the throttle body is fed by a 3inch pipe, if you cut a whole that was just about as big as the filter through the bottom of the stock air box and fender (but still retain the sides to protect it from the engine heat), it would feed that three inch pipe all it wanted, and the panel filter is still bigger than the whole it's drawing from, so it's surface area would not be restricitive until the size of the hole that fed the air, exceeded it's diameter. The only thing restricitive would be the permiability of the filter element.
Basically it's a short ram intake that is fed cool air, it's filter may be different than other short rams and CAI's but that doesn't mean that it would be restrictive for this application, just that round filters save more space.
But if you don't think this is true would, you could cut away the bottom of the stock air box, and attach a round filter to the 3nch port than runs from the box to the throttle body, would that satisfy?