sorry it took me a while to get you a response. i re-did my seats over last winter, and they are holding up really good. i just used a thicker dark fabric that could take some abuse. i wouldn't go with vinyl, because it will tear too easily. pleather could be a cheap substitute for leather, but i don't know how well it will handle cutting and sewing it.
as far as appolstering, after i got the seat cover off of the padding, i ripped the pieces apart, one at a time, with a seam ripper, and then wrote on the fabric where all the pieces match up. like A goes directly next to A, and i marked the order that i took the pieces off. next, i pinned the pieces to my fabric (so that i could still see the markings i made), and cut around them so that the new pieces were still pinned to the old ones. then i sewed the new pieces to the old, making the fabric doubly stronger. from there it's just a matter of matching the letters when your sewing it back together, in the reverse order that they were taken apart.
also, thick wire works just fine for replacing the metal rings that had to be removed when taking off the origonal cover.
a little bit of a pain, but well worth the results. i hope i could be of some help. if you have any questions, lemme know.