Have you guys tried running foams on the carpet with no traction compound? In my experience, it's a lot better than rubber and you don't get any marks. My club rents a carpeted church gym. We can't mess up the carpet so, no traction compound is allowed. The rubber class turned into a "sportsman" class because everybody hated running rubber. Our carpet sucks too. It's all stained up and the traction is terrible. I'd guess that carpet is 15 years old and it is seriously ugly. I don't know why they'd care about streaks, but the church set the rules. We run nitro touring car foam tires. The 26mm ones. On nitro cars, they run 26mm on the front, and 30mm on the rear. We just run 26mm all the way around. Most of us run 32 shore on the rear and 37 to 40 shore on the front. I give my car a few laps before the heat to warm up the tires. Once they are warm, they grip really good. The noobs don't seem to have an issue either. I don't know of any other clubs out there that run the tires we do, but it works great. I like the Xceed tires that they sell at A-main hobbies. Less than $8 a pair.