sell em here for $99 per set, Bee R brand
http://www.otomoto.com.au/beer.htm
from the website:
Adding these bushes to the rear suspension cradle in any RWD Nissan (and GT-Rs) from 1988 to 2002 reduces cradle movement dramatically to give a more consistent, predictable feel to the rear end, which is especially valuable for drifting. By altering the static angle of the cradle, pineapple bushes also promote rear suspension squat for greater rear grip.