There are only three possible benefits I can see to installing an aftermarket air filter, like the K&N: it is a permanent, cleanable, filter, vs. the cost of a disposable filter; it provides a performance benefit, either providing cleaner intake air, or more intake air, or both; it makes the owner-installer feel better.
Of these three, the most probable is the last. As for performance: the main restriction in the air intake is the throttle. Until the engine is at wide-open throttle, the air filter makes no significant difference in performance due to restriction.
As for cost, you can do the economic analysis yourself.
