Just my own opinion here on Eibach - I've recently installed 2 sets of Eibach springs on 2 cars- one new set and one used set - and to my eye, the nose of both cars still sits too high relative to the rear ride height. I've heard that this happens to some folks and not to others.
Upon examining the coils under load, the top 3 turns are fully compressed against each other, so it's probably a simple matter of cutting off a full coil turn to lower the car an additional 1/2" (the width of the coil itself), which would be a noticeable stance improvement. I'd venture to say that this shortening would likely yield minimal degradation of ride quality, given the full compression of the to 2-3 spring turns while under load already.