In fact racing bikes don't use pods from 15 years!!!
Every engine has a fluid-dinamically engineered intake (and airbox) volume studied for better performance.
The first thing is to calculate an air volume during engineering and dyno tests.
With this info the racing team builds an airbox that match the bike style and tank/frame shape. They dyno again the bike to find the better shape to match the flow and volume values given by the engine engineers.
Only into AMA races someone still uses pods.
I've obtained 132bhp and smooth power delivery with airbox mods, against 128bhp and nervous not constant power delivery using pods, on my Kawasaki ZRX1200.
The needing of bigger main jet doesn't mean nothing, it's only to compensate a bigger amount of air, but the combustion chamber and valve sizes don't permit better performance with bigger amount of air if they have reached the better performance at a lower air/fuel level.
It's not difficult to understand that adding holes to the airbox (and correcting carburetion at the same time) will rise power to an upper limit, raising it you can't obtain more power adding more holes or removing everything and using pods.
The job of a tuner is to find that upper level of performance possible with your airbox matched to your engine setup.
The right balance is where if you go lower or upper (with air/fuel mixture) doesn't give you any better gain.
