As for the springs and their actual drop any more than 1.5 and you are going to scrub the mufflers or cats occassionally and on speed bumps and High angled driveway. Just part of the trade off. Nowe are they progressive or specific?? Typically Progressive are great for a balance between handling and smooth ride but are not the best for handling.
It really depends on the type of driving you are going to do and the condition of the rooads where you live!!