There is a hairfit kit for V4 and Sydney from netherworks,  You can buy it on DAZ-website or on netherworks website, directly from netherworks is cheaper, but only possible with paypal.
hairkit for V4 is $5.50.  Works for all kinds of hair, as well hairprops as for figures, although the later is litlle bit work, I conversed Kyotohair from Kozaburo, and it works fine.
There also a V4 hairfit kit or several other hair at Poserpro's store from Freja, including Kozaburo's, but it only works on hairprops.
3dream has made his own V4 conversionkit for his own hair which is free and in the freestuff.
I agree that Kozaburo make wonderful hairprops , I wonder if he will adapt his hair for V4 and Sydney. Well, he has done it before, you never knows.

-How can you improve things when you don't make mistakes?