Superior in now owned by Lennox. Go to their website to " Find a Dealer" and i think you will find someone local to your area the sells and services your doors.
Hope this helps!
www.lennoxhearthproducts.com
Links: www.lennoxhearthproducts.com

If it is over a slab, buy or rent a large razor scraper and take it up.
If over a particle board underlayment you must take the vinyl and underlayment up first, then install tile backer or building paper and rib lath with a cement bed.
If over a plywood floor you can install the backer board directly over the vinyl flooring. I don't recommend putting a concrete bed over a vinyl floor for various reasons.

Tools required:
hammer, razor scraper, razor knife, lath or tin snips, tile saw, (wet cut saw the best), tile snips, grout float, thin set trowel, 2-3 5 gallon buckets, 2-3 grout sponges, rubber tile spacers, spacer removal tool, level, grinder, 1/2'' drive power drill, mixer paddle for drill, chalk line, framer's square, grease pencil, corner gage, caulking gun, hand truck to move tile, quality rubber gloves, knee pads, at least 1 helper and 2 cases of Molsen Golden (optional but recommended)