PK used the measurements to calculate a possible spring rate. You gave him all the necessary info except 1, the modules of rigidity of the materiel property of each spring. My guess is they are the same but you never know unless to test the actual spring and work it backwards. For what I see, they have comparable spring rates; 913 vs. 922.
As PK indicated, you need the free length of both springs before you say the newer springs are softer. to get this info, you would have to take the spring off the shock to measure the length of both springs. This is important as it tells you how much preload is placed on the spring.
Example:
Lets say the 2013 spring has a free length 7.15 inches and has a spring rate of 922 lbs/in. Once installed, the spring has a length of 7" (there are no preload adjustments). The preload would be (7.15 - 7.0) x 922 = 138.3 lbs. That means you would have to apply 138.3 lbs before the shock starts to compress.
If the 2014 spring had a free length of 7.2 inches and has a spring rate of 913 lb/in. Once installed, the spring has a length of 7". In this case, the preload would be (7.2 - 7.0) x 913 = 182.6 lbs. That is an extra 44.3 lbs of preload force per spring even. So, even though the 2014 spring has a slightly lower spring rate it is set up to outperform the 2013 spring as the extra 44.3 lbs of preload would carry over through out the working range of the shock.
BTW, there are a a few of us running much stiffer Eibach springs (500 and 550 lbs//in), Based on my experience, you need at least 450 lb/in springs.
Jerry
