your looking at between 1500 and 2 grand brand new not including labour for a good LSD for your r32, www.justjap.com have the nizpro ones, your better off going with the same approach i did which was buy an r32 gtr rear diff with the lsd, only needs few modifications to make it fit, there is a topic thread on here somewhere with the info, and you get a stronger rear end, but thats just my personal opinion
yt