There is a reason why the rear of the car is higher. I would not lower this unless you are planning on taking your car to the track. Here is my story...I lowered my car about 10 months ago. I used Koni FSD and also Eibach Sport springs. It dropped the car about 2 inches. I also replaced both the front axles because there was a mild vibration as a result of the lowering. The vibration never went away, but as a matter of fact they got worser. I got SPC adjustable cambers in the rear. I also purchase new Continental DWS lower profile tires, not dramatic but it was 235/35/17s. About 15K later the handling became worse. I had the rear tires replaced because the technicians indicated they were coning out and had some irregularities developing on them. Another 15K later the front end started to shake crazy. I was thinking hey, I'm tired of this, I placed back the rear springs. The handling improved somewhat, but then I put the original camber -2.5 back on. This was horrible. I took it again for a second set of eyes and they said that the tires were trashed. Too much vibration because of these tires, and also, the hard springs and suspension caused the damage....
I'm not sure how much money you want to spend, but don't think it will end with just the springs....