I dont thinks that is enough, i have cobb springs and i think it is looks great, i think it is like a 2inch drop! And they handle really well to and they are made for the stock struts! I am pretty sure for the perrin you need to put aftermarket struts and trim the bump stop on the strut!
enough is relative. what do you plan to do with the car? if its for street only application go as low as you are willing to deal with. the lower you go the more your going to ding up your skirts and body work.
if this thing ever sees gravel (as it should, its a damn rally car for crying out loud) i wouldn't drop it at all.
im not planning on doing to much track racing of any kind. just a nice street car that performs well at the drag strip and possibly a course of some sort. but i want it mostly for the street. just a nice cruiser that i can have fun with. so looks like it was my first choice the cobb before i heard bad on how they lower to much and such. thanks for all your input. Josh