i run a k&n and also a uni. when i went to the uni i saw no difference in jetting or performance although cleaning it was a little bit of a pain with the special cleaner. the k&n on the other hand eventually got gummed up because the cleaner you are supposed to use wan't doin it's job, i just soak it down with simple green to clean it now. all is good. never had a problem with them doing their job. i guess it's all personal pref.
hope this helps

steve