Bob,

My take as an interested party but someone not involved in any rules is simple: The class has mechanical limits on certain items. They stock variations of those motors exceed those limits so they are out. They have drawn their line in the sand. Having said that:

I am not sure why those motors can't be 'de-tuned' to max spec just like anything can be 'built-up' to max spec.

The chassis thing is still grey to me. S2000 is out but Miata is in? The STAC had a chance to eliminate cars of similar ilk like the FD RX-7 and the NSX last month when they put the Type-R chassis back in play...but didn't. Why? These aren't new questions but have seemingly gone unanswered.