I said it before, but I'll say it again: just copy the UF1 series rule set. One "realistic" class and one "open" class. No one is "discriminated" against unless they don't meet the width requirements (and tire) for each class. No restrictions on hopups, people can run whatever chasssis they want so long as they meet the rules. Easy no? You could even adopt the more stringent TCS rules; but that limits people to only two chassis.
That being said, my reading of what Dasmopar wants, is more of a true "spec" class, where everyone has similar chassis and equipment. Nothing wrong with that, but in my experience, spec classes generally encourage more cheating. I.e., One guy will break, skirt, or test the limits of the rules; thereby causing others to follow suit.