Did the same with mine and put on Orange piping to match color of car.
Not sure what the material is. Seems like some kind of foam with a carpet texture. Might be some kind of marine fabric. Honestly just glad to have the seats back. I had them professionally done. Took 3 months and supposedly shop "lost" my contact info. The seats really were not that bad to begin with but i wanted them in white and like new. I wish i had had them give me the old covers back, didnt even think about that. Came out to be more than i wanted to spend as well but oh well live and learn. They did come out great so in the end all is well.Yep. Very nice!
What did you use in place of the burlap on top of the springs?