ASD cars had LSDs. The LSD diffs are available new from Mercedes, GSXR had a good thread about it somewhere. Not sure what ratios are available from Mercedes. But you can swap the LSD carrier to your gearset.

The LSD works mechanically, so you do not need sensors.

However ASD cars also had a hydraulic pump and some sensors that would act as a true locker and completely lock the diff up to about 15mph. Otherwise its like 25% LSD at all other speeds.

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i