I used Sunmate medium density foam, 3/4" th on the seat backs. I could have gotten away using 1/2", but it works. It is FIA certified for flammability and other tests. I think it was $25-35. It is in my build thread.
http://www.sunmatecushions.com/colle...pedic-cushions
It seems I have some sort of magic timing; Adam posts about refurbing Elise seats, posts regarding Elise mounts in Miatas pop up, I guess it is an omen of some sort!
tsingson (08-10-2015)