This is one of the Mazda Tribute units that could be found on EBay about 3 years ago and can be adapted to work in a Miata. I used it in my car for about 3 years. The Changer unit inside failed at one point, but I replaced it and it works fine now. $150.
http://www.capefearmiataclub.com/tec...es/radio-f.jpghttp://www.capefearmiataclub.com/tec...s/radio-f2.jpg
Installation instructions can be found here.
