For the same price as a full set of bushes (nearly £1k) or a little bit more, I'd spend the money on suspension tweaks, ARBs, lowering/stiffer springs or coilovers and a good alignment. The improvement in handling from those will far exceed bushes, I'd say the bushes are more to compliment other handling tweaks.
I believe Jez from H Dev has a set on his car, but I think it was because he tracks it, there is a thread somewhere.
I'd only go for front bushes for the upper and lower control arms, compression arms and ARBs if you only want to do them.
As for changing them, you need a press to remove and reinsert the new ones (excluding ARBs), so either remove the arms and pay a garage to do them or buy a press.. Also important to get an alignment afterwards.
Edit - here http://www.350z-uk.com/topic/48020-superpro-bushes/