I am sure there is a DOT tire that isn't great in overall grip but lasts long. Avons? Nittos? RA1's? The REAL solution to the cost premise here is to do a one-time upgrade to 15" wheels and make 5 buddies in Spec Miata and use their take offs.

Another problem with allowing a tire like this is that you become a slave to the rules of another class. What if they change the compound and they become FASTER than they are now? Are you doing to know that? Are you going to outlaw them at that time? Are you going to only allow certain build dates?

It is a bad answer to a question nobody is asking IMHO.