Thank you Geezer, you have always been helpful with my questions.
Looking at the price of the part numbers from Ford, M-3000-ZXM is $395 and M-18000-ZXM is $549. Now from what you are saying is the M-18000-ZXM is only dampers where the M-3000-ZXM is the same dampers with springs. Looking at the price difference between the two the rational is not there. Why would the kit with more be less money? This is going purely off of logic here. I cannot believe that to be correct.
From it looks like the 18000-ZXM kit is more of a track only set of dampers where the 3000-ZXM kit is a street/track kit. I am guessing there is a llittle more valving or construction put into the 18000-ZXM dampers and that is where the value reflects in the price.