You can only recommend you contact the smog check referee office at (800) 622-7733. They may be able to offer you a limited parts exemption if in fact your Fiat X 1/9 emission components are hard to find. This will allow your to register your Fiat without a smog check. You will need to file for an exemption again in two years.
The referees office can also assist consumers with vehicles that have difficulties passing the smog check inspection due to unusual emission control component configurations.