probably about 1" rear and 1 1/4" front. every car is a bit different.
zim can chime in here. i sent him two sets of springs... one set i know was lost but the second... well, at this point i'm selling these i got in a few weeks ago and sending him the money. i am doing this on good faith. i buy and sell parts often and have an outstanding reputation. i moderate the classifieds on a texas mustang club site and this site. i understand your line of questioning though, that's what the "seller rating" is for.
basically what he said. I bought springs... they were lost in the mail. he went and bought another set for me to keep his rep up... those never got to me either. Now hes got these and is selling them and giving the money to me to keep his rep up.