Been using K&N filters for years... likely damn near a million kms between all the vehicles. NOT ONE SINGLE ISSUE. EVER. Buy one filter and forget it. Spring and fall, wash, oil and off you go. If you're getting oil on your sensors, you're over oiling the filter... PERIOD.
And for the record, I keep detailed millage recorded for every car/truck/van and bike for the last 20 years. EVERY SINGLE ONE of them has got better mpg, after switching to a K&N. And I've never bought another filter for said unit again.
One can of oil lasts me years... drop the $15 and carry on.
If wet filters are so bad, I wonder why most of my bikes have all come from the factory with them???? lol