Guys, I've found another lightweight seat option for the Z! The name of the company is Buddy club. They made racing seats for the 350z and have the ones for the 370z. They are a U.S. motorsport organization, so they are based in California. They seats are very light (according to the site, the seats weigh around 5 kg (12 lbs) each). They were designed for safety, lightness, and comfort. Unfortunately, for all you people who want a fully comfortable racing seat, this is a fixed bucket seat, so no reclining. Buddy club is not as popular or respected as Bride, Sparco, or Recaro, but I think the seats are really good. Very light...Carbon Fibre or FRP (Fiber reinforced plastic). Carbon Fibre seats costs $900 each, but the FRP only costs $500 dollars each. Here's the site..
---Buddy club OFFICIAL USA WEB SITE---
Go to products, then racing seats..
The site shows the rails for the 350z, but they are advertising the seat for the 370z, so I think they have the rails. Correct me if I'm wrong...