Well if you car is a daily driver, coil-overs can be hell.
Springs and shocks alone are usually the way to go.
Coil-overs corrode over time causing gauling on the threads and they are way stiffer then progressive springs do inpart to the relative meager amount of spring a coil-over can have. Adjusting coil-overs requires alignments each time if you want ideal camber and toe.

With your desired drop an Eibach or H&R springs is the idea solution. Unless you plan to seriously corner wieght your car for track use or have a hybrid combo, coil-overs aren't always needed. A Koni-shock/spring combo is going to outlast all but the most extreme external resivior coil-overs over time. High quality springs and shocks will set you back around 800-1000 dollars. To match this quality in coil-overs expect to pay double.