Limey Racing has released upgraded and stock replacement clutch packs for the R35 GT-R. The stock replacement packs will are rated at 620 ft/lbs, or about 650hp for $999. The LR850 upgraded clutch packs are rated at 800 ft/lbs or about 850hp for $1350.
The next thing I would like to see someone develop would be some carbon/carbon clutch disks and friction surfaces for the clutch packs. This would require some real re-thinking as they would not be a wet clutch surface, but then it might be possible to put a little heavier fluid in the trans to help cushion some of the gearshifts.
Source : Limey Racing