Used to have the 370z Roadster, and those seats were awesome for holding you in, comfort was decent and room was decent.
Now have a 370z coupe with the base seats, you seem to sit higher in them, driving position is not as natural (as many reviewers have said) and well they don't support you in the turns. (I'm 195lbs and 6'1)
If I were to choose a pair of aftermarket, it'd be Recaro Sportster CS:
http://www.tunerworks.com/products/i...52_01_4443.JPG
Honestly best seats I have sat in were ones that come with the Boss mustang (Recaro also)