I remember some member on this forum got custom carpet molded at
http://www.accmats.com/.
If you are going to buy aftermarket seats, spend the extra money and get a good one! Make sure before you buy the seats that the company you are getting it from has the seat brackets specifically for your car. It is better to buy local than online in these things so you can test how the seat feels and hopefully they'll allow you to test fit with your car.
I have had the WORST time with find brackets for my seats (Megan Racing - I like their seat, but I hate that companies support:
Me: "Hi, I just bought your racing seats directly from you and was wondering if you had seat brackets for them or at least could point me to someone who had one that will fit my 89 240sx?"
Them: "Most of our customers have to custom fabricate their brackets to make it fit."
There goes the $200 you saved on buying non-brand name seats.
Also, if some guy/seller tells you that you can modify your stock brackets to fit easily - DON'T listen to him! It is hard as hell to modify the stock brackets to fit an aftermarket seat. The whole assembly is completely different. Unless you have all the cutting, welding, etc tools to do it, it is going to cost you up the *** to get it to fit.
Whatever you get, get a brand that carries the specific bracket for your car.