The Turbo Esprit came with the Citroen C-35 transmission. As with many of the parts on the pre-GM cars the transmission is a little rare. If you have problems or issues, you might attempt to contact Harry Martens at http://www.ds-vitesse.com/home_uk.html
Quaife makes LSD for the C-35 Citroen transmission, QDF13H. In USA and Canada these LSDs are available from IMSservice@yahoo.com