As I say there are five motors, one for each door and one for the boot as well, as yours is a early Saph you will need them all if wanting the OE setup, the facelift models had a mechanical remote boot release and fuel filler cap from inside the car.

Yes if wanting remote CL via an aftermarket alarm etc then it depends on the alarm system I suspect usually they have a -12/+12 output for this, I personally on my setup have two relays (One for locking, one for unlocking) these connect into the CL wiring on a master lock and are tripped by the alarm unit when requested by the remote control of course, this then completed the CL circuit and locks/unlocks the doors accordingly. This is the same as what putting the key in lock would do.

Martin