[Greg Reid]

wovenweb, What do you use to wash your car?

rohrt,
I don't plug mine up when I wash it but of course I don't stream water directly at the openings either. I try to avoid rain if at all possible. When you look at your lower pan, you'll notice that there are some approximately 1/4" holes drilled around the perimeter to allow water to drain.
Good question about how well it breathes with the openings plugged. The foam is probably pretty dense when compressed by the hood and it might have an effect? I don't know and I don't plan to swap mine out for the closed ones. I guess if you use the magnet idea to attach the lower foam, you could just remove it when driving with the nostrils closed. You will then have a typical open element type breather under the hood.
As for the magnets, I just cut one up into small squares and glued them to the bottom of the lower foam. I figure when the foam is replaced, I'll just trash the magets right along with it. Some are stronger than others so just pick the best one you have around.