Q: Is the K&N foam gasket okay to leave in place when replacing with a foam filter?
I put in a K&N air filter a year or two back when I did a bunch of modifications. Now I want to go back to a foam filter, but when I removed the K&N and went to install the new non-OEM filter, I realized two things: first, I no longer have the filter cage, so I need to get that. Second, there's a thick sponge/foam gasket that goes around the airbox opening, obviously to create an airtight seal for the K&N. My question is, did this sponge/foam gasket come with the K&N and is it required (or desired) when I switch back to the foam filter?
A: The foam gasket came with the K&N filter. It isn't necessary with a foam filter but it won't hurt to leave it in there either.