I checked the GCR, but I couldn't find any reference to cars running in classes other than where they're legal. Can you point me to a paragraph?
I never said you have a choice. Obviously those running Nationals have to abide by the National rules. There is still a cost to the rules -- in this case, buying an extra set of tires so you can let them sit for a week after scrubbing, and dedicating a session each weekend to that scrubbing. I apologize if that fact doesn't fit into your happy-talk world.
You can read the GCR and find another class that a MIATA can fit in. You keep thinking I am talking about some exception to the rules.
Also, never said racing is cheap. Basically, said it serves no purpose to get worked up since there is nothing to debate. Doesn't matter the cost (percieved or real), Hoosier is the tire next year. To heat cycle Hoosiers in a method described by Hoosier will take at least two sets of tires and most likely two sets of wheels, no doubt. In the end you still have the options I listed. Bring your tires the way you want, cycled or not, 1 set or two; or not race. Period.
To sum up two facts which is all I am saying. 1) A Miata can enter another class other than SM. 2) No matter what it cost or how much of a pain it is (real or percieved), Hoosier is the SCCA SM spec tire for 2012. Nothing more or less.