I have one of these bad boys for sale - http://www.nismo.co.jp/en/products/competition/lsd/gt_lsd.html
4.083 ratio, comes in casing for S-bodies, with ABS / Speedo sensor, 6 bolt flanges, and I'll throw in matching driveshafts from my S15 for free if needed.
£550 including postage, no offers.