I was going to go the airtech route, but i'm really cheap. Tried to find neoprene sheets, but it's hard to find. Ended up getting a closed cell foam pad made for flooring in a gym or kids play area. ended up being under $5 for a 2'x2' piece. its about 1/2" thick. used 3m spray adhesive to attach it to the tail section i made. wish i had a better pic. made a template, cut it out with a razor blade, used a die grinder with a 3m 60grit disk to round the edge just a bit, put the textured side down. looks just like custom cut race seat pads.
Here is a link- http://www.greatmats.com/products/foamspecial.php