Board Thread:Game Discussion/@comment-5250791-20170710123004/@comment-29898480-20170718032020

SM = Spec Miata, an amateur road racing class in the SCCA and NASA for 1st and 2nd gen Miatas that are all prepared according to a fairly strict set of rules (or specifications, hence "Spec") that are meant to equalize performance and contain costs. For example, all cars must run the same competition spring and damper package, and engine parts can't be balanced or machined with limited exceptions. Performance equalization is achieved through restrictor plates and minimum weight rules. SM has had the highest car counts of any class for a long time, owing to low costs, good competition, and the car's incredible fun factor :)