As in the case of refueling/no refueling, the presence/absence of KERS in the championship is chosen by the league host and managers. DRS remains the same as in actual GP racing. But kers interfere with the realism of the races, turning the last laps into a crazy kers orchestra. Some like it, some don't. Who like it, let them race with it, who don't like it, race without it. Like the refueling rule and the two-tyre rule
well KERS may be not fair to some teams who started an non-refuel race with very low amount of fuel, drivers of those team can co crazily fast in acceleration and there may be other issues. So i think that only ERS/boost is enough