I would take it a step further and limit the N/A class just as much as possible to only those add-ons actually strengthening the integrity of the car in general or (better yet) nothing besides tires and safety equipment.
What this accomplishes:
'Bone stock' forces both the factory (those who would race off the showroom floor) and the aftermarket to actually compete (quality-wise) on a national stage. If your car or parts don't hold up; you'd better hire better engineers, bean counters or take some money out of your promotional programs (ouch).
UTV racing suddenly becomes the origins of NASCAR. Cheating is easy to spot, more women (OVER 1/2 THE POTENTIAL MARKET) jump in, qualifiers all over the country spring up overnight, the public identifies with the drivers, you could go on and on.
We have a story. Suddenly, it isn't a bunch of guys from out west with permanent suntans. The OEM class guys (which most will identify with) will earn rides in the big races and the big race guys will enter OEM races to 'prove' that they are indeed the better drivers..HP or not. The one thing that I miss from the NCAA tournament is the stories. Years ago, they would forego advertising money to offer up a tear-jerker. This sport needs those stories; nobody is strategizing as to the concept and it's a mistake.
We're dreamers. Every single story of success in this country will take you back to somebody loading up everything that they had in a trailer and doing something.
If we don't give Joe or Jill six pack the opportunity to do this locally or promote it heavily/fund simple compliance inspections (which the factory can help with immensely on the production line) then you'll never replicate the grassroots recipe that has already been proven.