i run 20" with h&r sport springs, would definately recommend them. they tightened up the handling so much and now the car does not wallow like a boat going around corners.
Due to you having the 3.5L, a slightly heavier engine than mine the drop should be just right, mine to be honest is just a little bit to high for me on the front, but apparently as i said the bigger engines can sit up to 1cm lower!
Go for H&r, Eibach sportline is to much of a drop in my opinion and prokit not enough.
hope this helps
