If Jeff Anderson (I believe that is the correct name) is still reachable
thru miata.net I'd give him a try. When I was dealing with the OEM stereo it
became obvious that this guy was the guru. He was also very reasonably
priced and good about getting your stereo turned around and back to you
quickly. Wow, these days that's considered too good to be true and it used
to be fairly common!

You can do a search for him in the forums probably easiest.

Good luck,
Chris
92BB&T