I have both set-ups(I have the coil-overs and my lady has the regular shortened struts) I'm pretty sure that they are both shortened the same amount. I don't think that they can be shortened more than two inches because then the Koni inserts wont fit. But you can lower your car up to four inches with the coil-overs, it wont be the best ride in the world but you can do it. I took a ride in Mike's (the owner of Motivational) ride and its low, and the ride is not horrible. You should drop him an e-mail, he is very helpfull. Here's a pic of his ride:
