In regards to brakes, the current consensus is to let the class get going and see where there is a need. One example we discussed was say a Ford Festiva with a 2.0 engine might really need bigger brakes, or a 1st gen Honda with a 1.8l might need bigger brakes?
No.
Either allow it at the start, or don't. It's a huge fundamental change.
Wheel fans, cooling allowances, fine. (But better in the ruleset from day one)
Decide on your cornerstones and stick with them. Time and again, people say they like consistency and stability in their racing classes and categories.
A fiesta needs bigger brakes? Well, duh, then chose a different ride, or put a smaller engine in it. Caveat emptor.
But don't as the keepers of the class, decide a year or two to just say, "OK, brake packages are allowed". (And use the dreaded safety card as justification) It changes the competitive balance, it throws away peoples investment, and it alienates the subscribers.
"Oh, now I need to run bigger brakes? (because, if they are allowed, and i want to win, I have to keep up with the Jone's, it's the rule of racing_)..well, now those wheels I invested in are too small, so THAT money and all the tires and testing are out the window, I need all new wheels and tires" etc etc.
And once that stuff starts, it's a slippery slope. IT has been around since 84 or so...and it's arguably one of the top two or three categories in the club. Rule changes come about based on technology shifts. The forefathers laid down a pretty good foundation, and major changes have been avoided wherever possible.
Beyond that STU allows bigger brakes, if I'm not mistaken, so for those who are hung up on tossing parts at the car, they can choose that class.