The debate over OEM vs. K&N air filters is one of those that ranks right up there with what type of oil to run, ABS and non-ABS, what aftermarket seat is the best, and shields and fairings on naked bikes
You can ask 10 people and get 10 different answers. If one or the other offered absolute proof of performance or economic advantage, there would be no debate. Use what you want and enjoy it!
2009 Honda Goldwing Four wheels move the body. Two wheels move the soul.