Purchase Leather Seats from one of the following vendors:
http://www.crazyred.com/cri/pages/
www.MiataMania.com
What type should I buy?
I recomend the "gathered" or "pleated" type leather for the center insert. This type last much longer than the super tight stock leather. I have the gathered type and it has already lasted longer than the factory leather.
How long does an installation take?
It takes about 6 hours. Plan to leave your Miata for 2 days at the shop.