I went with H&R Super Sport springs on my 96. They lowered the car around a little more than 2" all the way around. I also suggest getting a set of caster/camber plates at the sametime to get the alignment back in specs. I prefer maximum motorsports caster camber plates and that is what I run on my car. A nice set of shocks and struts should be on the list. I still run my stock struts and shocks for now but a set of tokicos will be going on soon.
If you do go with lowering the car this much you will have very little ground clearence. I have to be very careful when driving, especially when going into driveways or over speedbumps. My car only has around 3" of clearence from the x-pipe to the ground and it does scrape on stuff very easily.
Eibach springs (million mile warranty) (perferably Pro Kit so you don't drop too far)
And Koni Yellows for dampers.
See the presentation below for the reason to go with Koni's. http://www.koni-na.com/presentations/mustang/