Wow, what an active thread for the Unicorn section.
Just out of curiously, how many miles are you getting from your paper air filter?
I went to the K & N website to look at the horsepower gains they claim and found a page of disclaimers :-( seems the lawyers worked overtime.
K&N Published Estimated Horsepower Gains and K&N Dynamometer Test Results
It would make sense that you could gain a few horsepower at wide open throttle, if the filter is letting more air (and dirt) flow through. But this would do little at normal driving since the throttle plate restricts at anything below full throttle. With the new drive by wire systems, who knows what the non OEM filters do to the performance and MPG.