My First Autocross. Suggestions.

[talonTSIDriver]

I think you are getting confused.
For tires for competition use there are A-Compounds and R-Compounds. The A-compounds are used for autocross coursese and require a lot less heat to be sticky. However, these overheat fairly quickly and I would associate their grip as a street tire overheated when that is done.

yes, I'm sorry, the Hoosier's for auto-x use are the A6's meaning A-compound. My bad, The R6 are the Hoosier R-Compounds.

 

[Zero Bar]

Both of those tires are considered "R compound", just different variations of it. Like said the "A6" for autocross, it's softer and has a lower operating temp, and the "R6" for road racing that is harder and has a higher operating temp.