Have a diff casing and 2.56:1 crown wheel and pinion, originally from a 325TDS, excellent condition, casing has been modified to fit in place of a Ford Sierra differential. £100
Also have an E36 M3 limited slip diff in 3.3:1 ratio I think, complete diff in casing, £350.
Can post for considerable sum of money as very heavy or better if you collect from Letchworth.