It wasnt against red tire smoke as it was cheater compounds that are way stickier than regular compounds.

the smoke was cool, but the fact that they were one off tires and everyone knew it wasnt, the color of the smoke wasnt the reason those tires were banned.

the Maxxis Z1 Drift is under the same scrutiny right now, however Maxxis actually has production units available, unlike khumo who is just now releasing MX-C and ASX-C to the public, which is why back in 2005, they were banned.

now they arent a series sponsor so anything khumo is illegal.