it depends on the type of ride your looking for. Eibach spings give you a slightly stiffer ride from stock. H&R and progress springs give you a stiffer ride than Eibach because they were made for occasional track use, but is still good enough for steet. Progress springs give you a 1.3 inch drop front and rear. H&R gives you a 1.3 in the front and 1.2 in the back. Im not to sure about Eibach though but its most likly around 1.2 as well. In my opinion I would go with H&R springs,because they've been around longer, but really it doesnt matter because progress springs are good too.
I got progress springs. The drop is about 1.3'' all around and it is really nice. The ride is more agressive and a bit less comfortable. It is harsher but it really handles like a beast. From what I heard, eibach springs are not as agressive as progress and H&R. If you want, there is a rad deal for the progress springs at www.ptuning.com You get a discount if you are a member of msprotege.com
I have the H&R springs. They are firmer than stock but very comfortable for street use. They really improved the handling on the curves. The drop is 1.5 all the way around.