Do you need the whole assembly or have you looked at yours to see if just the one nylon gear is stripped of teeth, the norm? I've done one of mine on my 88 CE and now the other needs it so will be ordering a couple and I can sell you one for about $70. Let me know. These are good quality and work in all the coupes with the handover systems.
To get to the mechanism you have to remove the back seat, upper and lower, remove the top side chrome doorplate and the
inner panel. Slide off the belt carrier trim...it is soft plastic and gives easily in fact will wear out by the belt sliding in it. You can see the gears from there and don't need to remove it to replace the gear. Better if you don't as it holds it for you and you won't lose the adjustments.

Tobias MB
4 MBs