Ok listen close. The stock airbox can be altered in a few different manners. Here is what will and will not work, and has been tested on the dyno for accurate and non bs answeres.
1. Replace the stock air filter with a K&N Air Filter ($50) This will give you slighting better breathing...not enough to raise even 1hp, regardless what it states on their site. You may also have to adjust the pilot screws to get the air/fuel mixture accurate once you alter the airflow by changing the filter.
2. Remove the stock airbox and buy PODS (either K&N or UNI Pods each around $40-$50) These are supposed to "increase" air flow which means "more air equals more power" WRONG to some degree. Using pods will most likely result in you rejetting your bike and also messing with pilot screws again to fix the flat spots that you just created at 4-6rpm. These pods with correct jetting (which is actualy fixing a problem not making it have more power) can yeild a 1-1.5hp increase....mind you, you have a dyno and know how to install, and tune correctly. Jetkits and pods are a waste of time on this bike, adding more fuel or more air WILL NOT add more hp to this bike. Think for a second. Do you have more smarts than a team of Japanese engineers?
3. This is a proven self made mod done by a vet racer and many others (including myself). Take out your airbox, and then drill out a 1" hole on the right side (the side without the horn sticking out the rear). This lets the air flow better, and CAN add a slight 1-2hp increase. This has been dynoed, and proven. Here is the link.
I hope this info helps you in your discovery of ram air lol.