The wiring is a doddle to carry out DIY, as can use interior light feed.
The motor will need to come off a granada(mk3) or scorpio as the sierra ones that were electric to start with have a different number of splines so motor won't fit, unless you wanted to change whole sunroff cassete case over, the electric switch panel bit from sierra fits, but the reinforcing bracket holding the panel is the hard bit to get, but could always make one.
tabetha