It might be more of a space issue with the foam inside the small eco-racer. Thin foam seats collapse pretty easily and you might need to glass over the foam seat to retain the integrity. Our FSAE car also uses foam seat.....I do think there was little need for carbon fibre for the seat purpose. If anything regular fibre glass shell probably will do the trick, and be a lot cheaper....
University of Toronto Formula SAE Alumni 2003-2007
Formula Student Championship 2003, 2005, 2006
www.fsae.utoronto.ca