Merv, i think the reason the spring rates are high on the CR is the leveridge action on the shock, the angle is about 27deg off the verticle at ride height, spring compression is about 2.5" to the wheel movement of about 3.8". so a ratio of 1.5 Plus a fair distance from wheel to pivot point.
I plugged the dimensions into the spring rate calculator that was floating around here awhie ago, and came up with an ideal rate of 381 front, 406 rear, almost the same calc as Toperformance in Vic suggested to me of 375/400, so thats what i ordered, at $37 each from Summit, it wont be too big a hit if im out of the ball park.
My main concern was how far the car lifts for each mm of spring tension, must be calculatable.
Dave