SCCA's Milwaukee region ran it as an ITA sub-class in 1999 and the Cendiv Regional Championship Series will support it in 2000. The Souther Pacific Spec RX7 rules are now online. Don't be fooled by the term 'cheap racing'. There's no such thing. For those of us driving our street legal cars to the track beware, stuff happens.
Brake calipers fail, accidents, etc.
If you truly want cheap racing in a 'real car' then try Autocrossing. Spec Rx7 is not to be confused with the NASA PRO 7 class. We did get the class added to the American Road Race of Chamipions at Road Atlanta for the year 2000. The National SCCA web site has info on Club Racing. For more info see the Milwaukee Region page and the WAI pages here and here.