The drop isnt into the weeds, but imo its just right to give the car a lower stance while optimising the handling, any lower and you start to get negative effects, which is the point of the pro-kit. The Sportline kit they do is lower, but clearly its not going to handle as nicely.
As for running them on stock dampers, i'd think that as a temporary measure they'd be ok, although i'd be looking at swapping them out for something else, especially if the OE dampers have done any more than about 60-70k as they will be past their best by then...