To the best of my knowledge- and having participated in over 35 TCS events since the first one in 1994- Tamiya has NEVER relaxed their equipment rules. We've had shortages of tires in just about every class from year to year- Mini as well as Sedan- but somehow people manage to find tires or Tamiya gets in a last-minute shipment to the event.

My advice is to 1) ask your LHS what they have in stock or a firm commit from Tamiya to deliver, then 2) contact Tamiya USA & buy from them directly, then 3) go overseas to get what you're looking for, in that order.

Don't get caught waiting- be proactive.