Originally Posted by mixja
If I was lowering the car I'd probably go Eibach - the drop is in between the H&R and Dinan's, just right IMO... but everybody is different...
The thing is Dinan says they retain stock suspension travel specs by making other adjustments, namely, the use of shorter and modified (not just cut short) bumpstops and modified guide sports. To the best of my knowledge, no other aftermarket spring vendor deals with this. See Dinan's article here:
So, essentially, you end up with the same suspension travel, slightly firmer springs, and a subtle drop. They say the dampers work well with the slightly firmer spring. I am sure they've explored higher spring stiffness values to see where dampers stop working well with the springs as a system (from a performance and not necessarily a durability perspective), but I haven't seen any discussion on that from them.