I have measured up to 1.3 PSI incremental pressure over atmosphere in the air box of my ZX12 at measured speeds over 200 mph. I haven't bothered to measure them on a Busa, but I would expect similar numbers. 1.3 PSI of boost is huge, so saying ram air is not effective is silly. Airflow in the box is a different discussion from ram air boost. You can have both, and a good design will have both.
This discussion about fixing air leaks is somewhat flawed. With a high volume, low pressure system, even large leaks make virtually no difference. It may seem obvious that taping up the small holes would make a difference and increase pressure, the fact is that the pressure in the box (only around 1 psi) is sustained by the air pressure at the front of the vehicle. You have a 20 liter balloon with small leaks in it, but it is only holding a small amount of pressure. No dyno result exists that shows one iota of difference.
Unless you route the crankcase vent elsewere, the box is never sealed up anyway. For what its worth, routing the crancase vent to the PAIR valve is worth 1.5 HP due to reduced pumping on the back side of the piston, but an airbox at 1 psi does not need to be leaktight.
