I have the Ground force 1/3 Kit for harleys and lightnings (Front: coils, shocks. Rear: shackles, hangers, shocks) on now and its at 17" in the rear.

What could I do to get 1"- 1.5" more drop in the back????

I was thinking maybe:
-Belltech or Roush leaf springs
-JLP 4" shackles