I am obviously biased toward Twister and I'm not attending this race but I would bring this up about any race with any other tire as well.
If you're going to have a spec race but allow non kyosho tires at all, why not allow all tires that meet a certain size or other requirement so the racers can have the choice. I say this because there used to be a monster truck tire that was half the size of a normal one that was completely unfair so we can't just have everything but saying 3 of 4 brands are acceptable but not the other is odd.