Polybushes
I tried poly bushes from Milner Off Road on my R3mR I know my rear suspension is different to yours but I found that using them on the long rear arms made the ride unbearably hard so ended up using the Genuine Nissan ones for the long arms and poly bushes for the short rods that hold the axle in place.
The bolts and nuts that came with Milners poly bushes were much cheaper than using Nissan bolts for the rubbers so the cost of buying the complete set of 8 poly bushes was not completely wasted.