I think the tire issue will be the next hurdle but first we have to clarify this motor thing I think most people here are missing the point, there will be no change of bodies do to the fact that this will not lower the cost, there will be no spec tire rules do to the fact that this will not lower cost.
This class purpose is not to create a class for beginners, this class is attended for people who are not ready or willing to spend hundreds of dollars on high end motors. This class is also attended for more of a equal playing field, no modify motors and limitations on the ports. The sedan class has port limitations but we don't call that a spec or sportsman class.
You can race both classes if you like all you have to do is change engines.