Most of the Ford springs are linear or don't have enough rating to be decent (i.e. B's in some applications). I like the Progressive rates (like
Eibach's) because I personally feel they are less harsh if they use decent rates. When a car has a 2" drop, it sucks when it feels like riding a rigid frame bike.
We should note that I'm older than most here and dont generally tolerate misery like I did as a kid.