I chose the 2nd option.

Of course there are more issues than a poll can address here, if someone chooses the first option:

1. Identification of the what class a car is racing in
2. Compatibility of safety regulations
3. Educating the 'host' class competitors of the new ruleset so that they may appropriately police the class.

Simply by making selection #2 these all disappear. Your SM/SMT/SM?? car meets IT rules? Great come race IT. Your IT car meets Prepared rules? Great come race Prepared. Your IT car meets Prod rules? Great come race prod. Your LP Prod car meets IT rules? Great come race IT.

So easy and logical that way.