Ever thought about getting these for the Miata build?
http://www.racingbeat.com/resultset....rtNumber=11061
Which block are you guys using? There have been good results using the RE block in NA form with either 9.7:1 S5 NA rotors or some special 10.2:1 Rotors that KDRotary had used in an NA 20B build. Methinks they were just 10:1 rotors though.