First of all, you want the heavier springs in the rear.
See, if only suspension and tuning topics were this easy I'd actually get it. LOL With the suspension design on my car, Koni recommended running higher spring rates in the front. Curently I'm using 750 lbs front, 600 rear with a stock bar and have no problems getting the tail to come loose. My original suspension was running 400 lbs front and 600 lbs rear.