<font face=\"Verdana, Arial\" size=\"2\">So I assume that means the tires will be kumhos and toyos for Spec Miata yes?</font>
Why would you assume that? As I recall, the nationally-published Spec Miata rules give regions "the option" of specifying a tire, however unless otherwise specified there is no tire manufacturer restriction.

Further, the 2004 ARRC was run with open tires and Hoosier's SM ruled the weekend...