The more I read into this I see the only real reason to change this rule is new cars itc beetle maybe and a few itb cars that may come with wider than 6" wheels and bigger than 15". Finding a 16 or 17 x 6 wheel may be harder. Almost everything else can be found either by junkyard shopping or careful looking for odd sources of wheels. They can be extremely expensive no matter what you make the rule. If you carry the thinking to allowing oem wheels as ok then you don't have to worry about that problem. you could allow anyone to run 15" wheels in itb/c and that may eliminate the search for narrow larger diameter wheels. The fact that if you look in junkyards/online most vehicles can get a less than 15lbs wheel for less than 200 dollars i'm not sure what we have is broken. People will always spend more for an advantage. I sure don't wanna buy 15x8 inch volks to fit 275/35 15 inch hoosier a6's on an itc car. No I don't ever think that would really be necessary but that rules out opening it up. That and I'm guessing if Mr. Amy wants to send me his car and a big enough check you can fit a 15x7 with a 225 tire(2" springs and very very rolled fender, maybe more negative camber with the strut/offset with lca bushing to adjust back). Just upped the cost more. I don't think open or bigger rules fits the IT ruleset until most new cars competing are "downgrading"
I'd like to know if the newer cars 2000+ (that will be itb/c cars) are going to have problems getting 15x6 inch wheels to fit over brakes, and how many came with larger wheels than that in either width or diameter than that from the factory. The only reason I see to change this is for the next grouping of cars that will be classed in itb/c

Brian