What I told our local track owners was do not force the class into spec vs mod. Start out open. Build the class and let it evolve. Not everyone lives in Cali or the other hotbeds where you can get 4 heats of 4wd buggy every week, so I think that the way to ensure the class grows is to just leave it grow naturally. Trust me, the racers will speak up. Once there's enough, they will definitely gravitate one direction or the other....