Washable filters are extremly overhyped. On engines in low state of tune a less restrictive filter can help power/economy since the engine doesnt have to suck air as hard.
In an engine that is in a high state of tune, a great deal of power comes from overpacking the cylinder. Designers use any trick they can to cram more air/fuel into the cylinder than it would normally hold. One of the ways of doing this is to force the air/fuel mixture to run down a long skinny tube. The air builds a great deal of momentum, since it is flowing real fast. Once the cylinder fills up, the air is still flowing down the tube, and continues to cram into the cylinder, yielding more power. The trade off is that all that momentum ruins throttle responce, so the engine feels less "snappy". This is partly compensated by using larger and larger airbox.
Another way to overcram the cylinder is to use the sound/pressure waves. When the intake valve opens, a "pop", a pressure wave escapes the cylinder and travels up the intake, then it gets to the airbox, bounces off a few times, and eventually starts traveling back down the intake. If everything gets timed just right, it will arive at the intake valve right before it closes, giving the cylinder one last push of air/fuel. This description is oversimplifying things, but you can see that its a pretty delicate process. By changing the resistance of the filter, and especially by changing the shape of the filter, this delicate balance gets knocked off. After that, its a matter of chance, sometimes things could improve a touch, Since bike manufacturers have noise standards to deal with and couldnt tune the engine for max power, but most of the time, the power will go down a notch, since filter manufacturers can't put as much time and money into r&d, as the engine manufacturers do. They just copy the paper product, slap a bunch of silly claims on the box, and look for suckers that think they can be so much cooler if they spend an extra $50 on their filter.
At the end of the day however, a better rider will be faster on a slower bike than the opposite. Even extensive engine modifications make very slight difference on lap times. The biggest improvement you can get from parts in terms of lap times would be better tires.
Forget getting aftermarket stuff for you bike, save that money and go do a few track days. Is it better to compare how fast your bike could go, or how fast you can go on it?