We invented SM2 as an Atlanta Region class last year at the request of some '97 & earlier owners who felt they were not competitive against the later cars. It was debated heavily back on SpecMiata.com and I'm not going to open that door again.
For awhile we had two versions of SSM - the NASA version headed up by Jason Holland and the DC Region version. There were some differences between the two but both versions are much more restricted than the SM rules.
We've had minimal participation by the NASA guys and now that Jason is pursuing other options the NASA version is on life support if not dead. The DC version is very much alive and well, however (often outnumbering SM at MARRS events), and as long as 5-10 of those guys continue to show up for the ARRC (we've averaged 7.0 over the last three years) I have no problem giving them their own class.
Thus ends today's history lesson on SM2 and SSM...