The "Goodwin Racing" performance intake now sold by Moss
Motors was developed on my Miata and I got to keep the
prototype when they were done.

I don't know about the warranty.  Moisture was never a
problem.

I have to say, though, that it didn't make a noticeable
difference in performance.  At WOT it sounded cool, but its
foam element cone filter couldn't be as effective a filter
as the stock air cleaner, so I took it off.  I'm happier
with the K&N filter element I now have.