Most (not all) K&N filters come pre-oiled, new out of the box. The K&N F.A.Q page implies when over oiling occurs, let it sit. They also state there is no evidence of their reusable products creating issues with MAF sensors, but apparently other people disagree.
https://www.knfilters.com/faq
https://www.knfilters.com/maf/massairfindings.htm
The FAQ also states you could throw some error codes just by installing their filter for a variety of reasons.
I would think using one that is pre-oiled, new out of the box, poses less risk than you oiling it yourself, especially the first time.
I would also assume when you wash it the you could not get it clean enough leaving dirt and soap residue in the filter media before even getting to the oil application.
There are many of these filters in use on all types of cars but you have to ask yourself with the Z/28, if the K&N reusable filter was that much better why did the GM engineers opt for the dry filter instead, also made by K&N supposedly? They were already throwing all kinds of performance parts at the car and asking $76k for it, I don’t think another $20 would have broke the bank if the performance gains were that substantial. The same is to be said about this K&N product for our cars:
https://www.knfilters.com/blog/get-a...ur-z28-camaro/
I would be curious to know if another member here ever purchased one and what gains were observed.