Originally Posted by JAJ
We're doing exactly the same math. Zero preload, zero drop = 200#, zero preload, 1 inch drop = 160#.
According to the advertising, Eibach drops the front 0.8" (yielding 166#), H&R drops it 1.0 # (yielding 160#) and Dinan drops it 1/2" (yielding 177#).
Dinan is the only one of the three with the opportunity for stiffer than stock springs, and there's no way to know if they actually stiffened them or if they did a shorter stock-rate spring and a smaller pre-load.
OK. The reason I specifically picked 0.25" drop is because I think that is what the Dinan spring does. My understandings is that the other 0.25" is supposed to come from the shaved guide support (I haven't taken one of these assemblies apart, so I am not certain of the details), and the total drop ends up being 0.5". The Dinan springs indeed feel slightly stiffer than stock. I jacked up the car last night, and they do have preload--not sure how much. So, my guess is that there is some preload to keep them in there, so they are about 10% stiffer.