Hi there
Try using a Stillen front lip from
www.stillen.com I have one fitted to mine, the car has been lowered by 3"and I have 18" wheels fitted and at it's lowerest point on the lip is 120mm or just under 5" which is about as low as you want to go. I have trouble now and then with judder bars and drive ways as it is.
Not sure on price U.S but in New Zealand they sell for $900.00
Primera Man