I would guess that the r34 had a replacement twin disk installed, very common in those. On my r32, the stock clutch is quite light. But the fk8 clutch is still lighter and easier to drive than my skyline.
I'm on the 18" because of race tire prices.
They do a bunch of cool powdercoat colors too, check them out https://www.flickr.com/photos/vmrwheels/sets/72157627001100117