Mike,
You may use the Tune Hard Spring Set. Look on our TCS website for exact rules on this class. On carpet track you don't have to use the B3. You may use the A or C compound.
have a couple questions about pro-spec class
do we have to use only the 5 coil croum spring??
are can we use the tune spring set..
also for carpet tracks can we use type-a tires?? b3 don't work well on carpet
thanks
Mike Masters
ps I hope to make it out for nationals this year