The brochure linked is ONLY for s2 R34's.
S2 R34's are pretty rare to begin with. They were only made for like 6 months, Late 2000 to early 2001.
99% (no idea on the number) of R34's are S1's.
I've had both diffs (well, I had a S15 diff, but its the same center...) and I actually prefer the VLSD... when it's working as the one in my car was/is in good condition (for now).
The predictability was really quite noticeably better than the Helical diff, which likes to inside spin REAL easy, which isn't really a problem at 150rwkw with good tyres, but dial it up to 400 then try and take a corner under power and then you'll find the back end being nice and unpredictable which is quite undesirable.