I've been testing my Harrison the last few weeks and there are a few squeaks coming from the R33 rear suspension (not reconditioned) as well as noticeable squirm under moderate power and when transferring weight or going over undulations in the road. Rather than start a new thread I thought I'd add some info here.
Taken from an eBay listing, "The stock Nissan rear subframe bushes contain silicon-filled Rubber Bushes. Even on stock HP GTS-T's, the stress of putting the power down twists the rear subframe- punishing the subframe bushes. The rubber perishes and the silicon leaks out- this leaves an air filled void that can lead to vague handling and a loud knocking from the rear on really bad examples".
So given that this is a 15 year old cradle, I'm going to source some poly bushes from eBay. A UK seller has "85 shore A" duron bushes with alum inserts and steel washers delivered for about $80 AUD. More info on duron ratings below.
Shore (Durometer) hardness test [SubsTech]
Next stop are the upright and control arm bushes, pictured below. Two lower control arm bushes per side (green dots) and 4 upright/control arm bushes per side (red dots). Roughly $15 a piece.
Interesting info from Whiteline below on ways to "shim" the rear cradle for desired road holding behaviour.
http://www.whiteline.com.au/instruction/203a_KCA349.pdf
I plan to make these changes in a few weeks once I'm through engineering, will post my findings after that.