The Xtreme organic kit for the DE is rated to over 400 ft-Ib and we have this running in a few FI Zeds, it just depends on how it will be driven. It can be seen here
http://www.350z-uk.com/topic/95545-new-xtreme-clutch-organic-inc-smf-350z-de/
If you want the ultimate that's still nice to use then the 200mm Twin Plate kit is rated to 800 ft-Ib, it can be seen here http://www.350z-uk.com/topic/95787-xtreme-clutch-twin-plate-200mm-ceramic-350z-de-799/
Techniclutch would be one to avoid just Google them, they have been caught out selling fake Exedy kits. As the old saying goes you get what you pay for