I cut one coil from the front, it got me about an inch or so drop, which is all I was after...
Park your car and peek under and look at the spring... measure the coils from the bottom and decide how much you'd like to lose.... I cut mine with a dremel. (off the car, obviously...)
It's a pain, but take it slow: maybe go 1 or 1.5 coils, put it all together, test drive, see how you like it, decide if you wanna go lower...
at least you're in a good spot where you have a spare set to go back to if you go too low....
Also, it's been my experience that whatever shocks you're running, even if they're nice, will die a quick death if you lower the car, as they've "gotten used to" riding at the previous height...