The dealer was right in this case. Make sure you oil only the fresh air side of the filter. Don't over oil it. Do let it dry before reinstalling it.

K&N had some dyno posts for some vehicles. Usually it shows HP increases maximum over 3500 RPM and minimal at 2500 RPM. Since my tach reads 2000 rpm at 70, I don't see how the K&N type filters will help out most of the time. I will change the factory filter about every 2000 miles.