can one find black carpet and floor mats for the FD???

And how much.

 

Mazda doesn't sell floor mats anymore. They also charge over $1000 for carpeting (or about $850 or so through Malloy Mazda/Mazdaformance).

You can pick up floor mats from Mazdatrix for about $55 that are better quality than stock but don't have the "RX-7" logo embroidered on them.

You can also get custom carpeting of much higher quality than OEM for less than Mazda wants for the nappy stock crap. Do a search in the Interior forum using "carpet" under username "gmonsen" for an example of cheaper custom carpeting.