Off of K&N's site
26. Should I install the largest K&N filter that will fit in my race vehicle?
If an existing K&N filter is large enough to provide negligible restriction, a larger than required filter will not affect the amount of air an engine can take in, however, it will lengthen the filter's service interval. A longer service interval can be an important factor when racing in dusty, dirty environments.
To each their own. obviously.. the larger filters dont hurt. Do what you want.