Well, if you want to keep it "cheaper" then don't allow an aftermarket shock either. The cost of one crash due to crappy stock suspension isn't going to be cheaper than a set of emulators anyway. But even if I decided to race in the production class with the "no emulators" rule in place, you can bet that I'd custom mix the fork oil viscosity to get the best performance out of the front end.
I'm well aware of the whole snorkle thing with WERA. I was speaking specifically about suspension and not modifications for more power. But really the choice of a CBR250 for the class is a somewhat self-inflicted horsepower handicap anyway. If someone is going to complain about suspension when they're on a CBR250 giving up at least 15 horsepower to an R3 or the RC390, it's pointless.
If you want "fair" then about the only way to really do that is a spec class where you can change NOTHING. When I was in Germany in the 1980's they had what they called the Castrol cup. You bought everything as a package: Bike, suspension, tires, riding gear, oil, ets. You had to use the same gas too. THAT was some close racing. I realize that it would be nearly as cheap as buying your own bike and setting it up, but it would certainly help level the playing field if that's what people realy want.
I'm not really sure what people mean about "racing for fun" anyway. As if there are people who race because it's not fun. I've always raced for fun. I've discovered winning is fun too. As I said, if I were to race in the production class I would focus on using the rules as they are written and maximize my chances of doing well by my bike choice and setup within the rules. And if I were to find that my competitors are not racing according to the rules, well I would protest. IMO, those who haven't protested about the emulators when they know that someone else is not following the rules have no place to complain. I've heard it many times before where racers think that somehow it's unsportsmanlike to protest, but then they complain about others cheating.
There is a right or wrong answer in club racing. If you don't like the way a class is run, then do something about it or go find a class that you do like. When I was racing an SV650, people were complaining about getting whippped by very expensive 1000cc Ducatis when that's what the CCS rules allowed. Those people could simply choose to vote on what they think about how the class is run by racing with another club or in another class. Instead, they continue to race in a class where they get their butts kicked and then whine about it. Now I'm not going to spend $50,000.00 on a racebike, but I won't fault the guy who worked hard and earned enough money to choose to get the bike that would give him the best chance to win in that class. I just raced elsewhere.
This season I made the choice to run in a class where there are more open rules that allow creativity and I think that our team's bike did fairly well in never finishing off the podium. I didn't spend a lot of money doing so. It was a total blast and I plan to run in the class again next year only with a much improved bike. All within the rules.